216 outputs the communication signals based on parameters, such as battery pack voltage, battery pack current, battery pack temperature, etc. In some embodiments, the fuel gauge IC 216 is electrically connected to the node 207 that is electrically disposed between the at least one blocking device 208 and the one or more electrochemical cells 206.

In some embodiments, the fuel gauge IC 216 may determine a state-of-charge of the battery pack 20, and may predict how much longer, under specific operating conditions, the battery pack 20 can continue to provide power. In some embodiments, the fuel gauge IC 216 may further determine a state-of-health of the battery pack 20, and may provide a notification in case of deviation in the state-of-health of the battery pack 20 from a standard state-of-health of the battery pack 20.

In some other embodiments, the fuel gauge IC 216 may monitor the battery pack voltage, current and temperature. In some other embodiments, the fuel gauge IC 216 may store all relevant information pertaining to the battery pack 20 in an associated memory element for retrieval by a controller.

In some embodiments, the battery pack 20 is configured to switch between an active state and an inactive state. In some embodiments, the fuel gauge IC 216 outputs the communication signals in the active state of the battery pack 20, and the fuel gauge IC 216 does not output the communication signals in the inactive state of the battery pack 20. For example, the inactive state of the battery pack 20 may correspond to a dead battery condition of the battery pack 20. Thus, the fuel gauge IC 216 does not output the communication signals when the battery pack 20 is in the dead battery condition.

In some embodiments, the battery communication lines 214 are inter-integrated circuit (I2C) communication lines. Generally, the I2C communication lines transfer data between a controller and one or more ICs in an electronic circuit. With reference to FIGS. 1A and 1B, the battery communication lines 214 include at least a battery serial data (SDA) line 214a and a battery serial clock (SCL) line 214b. In some embodiments, the battery communication lines 214 may include another line which is ground or 0 volts. Generally, an SDA line is used to transfer relevant data between a master controller and a slave device. Generally, an SCL line carries a clock signal which can synchronize data transfer between the master controller and the slave device.

In general, I2C communication is a serial protocol for two-wire interface to connect low-speed devices like microcontrollers, electrically erasable programmable read-only memories (EEPROMs), analog-to-digital (A/D) and (digital-to-analog) D/A converters, input-output (I/O) interfaces and other similar peripherals in embedded systems. I2C communication can be used to connect an almost unlimited number of devices, including at least one master device and at least one slave device. Each I2C slave device has a unique address, and the master device can have access to the unique address, such that the master device can read or write data at the address of a particular slave device. Serial data is generally transferred from and to the master device. Serial data is typically split into 8-bit packets.

The charger 10 supplies power to the electrochemical cells 206 via the battery input line 202. In some embodiments, the battery sense line 204 is electrically connected to the battery input line 202 between the one or more electrochemical cells 206 and the at least one blocking device 208.

With continued reference to FIGS. 1A and 1B, the charger 10 includes a charger IC 102 including an input pin 104, an output pin 106, and a sense pin 108. In some embodiments, the charger IC 102 is an integrated host-controlled charge controller. In some embodiments, the charger IC 102 is an integrated host-controlled charge controller with two integrated N-channel power metal-oxide-semiconductor field-effect transistors (MOSFETs). In some embodiments, the charger IC 102 provides a constant-frequency synchronous pulse width modulator (PWM) controller with high accuracy regulation of charge current and voltage. In some embodiments, the charger IC 102 may monitor a temperature of the battery pack 20 to allow the charging only in a preset temperature window. In some embodiments, the charger IC 102 may include a thermal regulation loop to modulate the charge current to maintain a predetermined junction temperature during the charging of the battery pack 20. In some embodiments, the charger IC 102 may include other pins in addition to the input pin 104, the output pin 106, and the sense pin 108. The other pins may include a charging status pin, a temperature qualification pin, a charge mode selection pin, a cell selection pin, an analog pin, and the like. In some embodiments, the charger IC 102 further includes an enable pin 109. The charger IC 102 can be activated or deactivated by providing a control signal at the enable pin 109.

The input pin 104 is configured to be electrically connected to a power source 23. The charger 10 further includes a power supply line 110 configured to supply electrical power from the power source 23 to the input pin 104 of the charger IC 102. In some embodiments, the electrical power is supplied from the power source 23 to the input pin 104 through a current limiting resistor (not shown). In some embodiments, the power source 23 may be a 240V wall unit. In some other embodiments, the input pin 104 may receive the electrical power from the power source 23 via a power brick (not shown) associated with the charger 10.

The charger IC 102 is configured to provide an output voltage “Vo” at the output pin 106. In some embodiments, the charger IC 102 is configured to control the output voltage “Vo” based on a voltage “Vs” detected at the sense pin 108 of the charger IC 102. Specifically, the voltage “Vs” detected at the sense pin 108 of the charger IC 102 is based on a voltage drop “Vd” across the at least one blocking device 208. For example, the voltage “Vs” detected at the sense pin 108 may be substantially equal to a difference between the output voltage “Vo” and the voltage drop “Vd”, i.e., Vs=Vo−Vd. The battery sense line 204 is configured to detect the voltage drop “Vd” across the at least one blocking device 208. For example, for a battery pack 20 that requires a battery voltage “Vb” for full charging, the output voltage “Vo” is a function of sum of the voltage drop “Vd” and the battery voltage “Vb”.

Therefore, by detecting the voltage drop “Vd” across the at least one blocking device 208 and the voltage “Vs” at the sense pin 108, the charger IC 102 can select and provide the required output voltage “Vo” at the output pin 106. In an example, the output voltage “Vo” may be greater than or equal to a sum of the battery voltage “Vb” and the drop voltage “Vd”, i.e., Vo≥Vb+Vd.

In some embodiments, the one or more electrochemical cells 206 may be charged by a charging voltage “Vc” applied at the node 207. In some cases, the charging voltage “Vc” may be substantially equal to the battery voltage “Vb”. Further, the at least one blocking device 208 may allow a unidirectional flow of a charging current “Ic” from the charger output line 112 to the one or more electrochemical cells 206 of the battery pack 20 for charging the one or more electrochemical cells 206.

In some embodiments, the charger 10 further includes a charger output line 112 electrically connected to the output pin 106 of the charger IC 102. The output voltage “Vo” provided at the output pin 106 is further applied through the charger output line 112. In some embodiments, the charger output line 112 is configured to be electrically connected to the battery input line 202 upon coupling of the battery pack 20 to the charger 10. With reference to FIG. 1B, the charger output line 112 is electrically connected to the battery input line 202 when the battery pack 20 is electrically coupled to the charger 10. In other words, upon coupling of the battery pack 20 to the charger 10, the output voltage “Vo” is applied on the battery input line 202 and the power is supplied to the one or more electrochemical cells 206. In some embodiments, the charger output line 112 may further include one or more resistors (not shown).

The charger 10 further includes a charger output terminal 114 electrically connected to the charger output line 112 and configured to be electrically connected to the battery input line 202. Specifically, with reference to FIG. 1B, upon coupling of the battery pack 20 to the charger 10, the charger output terminal 114 is electrically connected to the battery input terminal 210. Further, upon coupling of the battery pack 20 to the charger 10, the charger output line 112 is electrically connected to the battery input line 202, via an electrical connection between the charger output terminal 114 and the battery input terminal 210.

In some embodiments, the charger 10 includes a charger sense line 116 configured to be electrically connected to the battery sense line 204 upon coupling of the battery pack 20 to the charger 10. With reference to FIG. 1B, the charger sense line 116 is electrically connected to the battery sense line 204 upon coupling of the battery pack 20 to the charger 10. Further, in some embodiments, the charger 10 also includes a charger sense terminal 118 electrically connected to the charger sense line 116 and configured to be electrically connected to the battery sense line 204. Specifically, upon coupling of the battery pack 20 to the charger 10, the charger sense terminal 118 is electrically connected to the battery sense terminal 212. Further, upon coupling of the battery pack 20 to the charger 10, the charger sense line 116 is electrically connected to the battery sense line 204, via an electrical connection between the charger sense terminal 118 and the battery sense terminal 212.

Referring to FIGS. 1A and 1B, in some embodiments, the charger 10 further includes an analog switch 150 electrically disposed between the charger sense line 116 and the battery sense line 204. Specifically, the analog switch is disposed between a connecting section 117 of the charger sense line 116 and the battery sense line 204. Further, the analog switch 150 is disposed between the connecting section 117 of the charger sense line 116 and the charger sense terminal 118. In some embodiments, the analog switch 150 may be a low resistance switch. In some embodiments, the analog switch 150 is a single-pole-double throw analog switch. In some other embodiments, the analog switch 150 is a single-pole-triple throw analog switch. In some embodiments, the analog switch 150 may be implemented by using a field effect transistor.

In some embodiments, the charger 10 further includes a microcontroller 180 electrically connected to at least the charger IC 102 and the analog switch 150. The microcontroller 180 is configured to sense the battery pack 20. In some embodiments, the microcontroller 180 is electrically connected to the analog switch 150 by a control line 181. A switch state of the analog switch 150 is generally controlled using an output of the microcontroller 180. While the subject matter is described using a microcontroller, other types of processing or discrete logic can be used for the microcontroller function, including, but not limited to, a processor or microprocessor.

In some embodiments, the microcontroller 180 is further configured to deactivate the charger IC 102 until the battery pack 20 is sensed by the microcontroller 180. In some embodiments, the microcontroller 180 is further configured to activate the charger IC 102 upon sensing the battery pack 20. In the illustrated embodiment, the microcontroller 180 is electrically connected to the enable pin 109 of the charger IC 102. The microcontroller 180 can disable or enable the charger IC 102 by providing a control signal at the enable pin 109.

In some embodiments, the charger 10 further includes one or more charger communication lines 182 electrically connected to the microcontroller 180. The one or more charger communication lines 182 are I2C communication lines. With reference to FIGS. 1A and 1B, the one or more charger communication lines 182 include at least a charger SDA line 182a and a charger SCL line 182b. In some embodiments, the one or more charger communication lines 182 are configured to be electrically connected to the corresponding one or more battery communication lines 214 of the battery pack 20 upon coupling of the battery pack 20 to the charger 10. With reference to FIG. 1B, the charger communication lines 182 are electrically connected to the corresponding battery communication lines 214 of the battery pack 20 upon coupling of the battery pack 20 to the charger 10. Specifically, upon coupling of the battery pack 20 to the charger 10, the charger SDA and SCL lines 182a, 182b are electrically connected to the battery SDA and SCL lines 214a, 214b, respectively.

In some embodiments, the microcontroller 180 of the charger 10 may be considered as the master controller and the fuel gauge IC 216 of the battery pack 20 may be considered as the slave device. With reference to FIG. 1B, upon coupling of the battery pack 20 to the charger 10, the relevant data of the battery pack 20 stored in the fuel gauge IC 216 is transferred from the fuel gauge IC 216 to the microcontroller 180, via the battery and charger communication lines 214, 182, when the battery pack 20 is in the active state. Specifically, the relevant data of the battery pack 20 stored in the fuel gauge IC 216 is transferred from the fuel gauge IC 216 to the microcontroller 180, via the battery and charger SDA lines 214a, 182a. A clock signal is set by the battery and charger SCL lines 214b, 182b to synchronize the data transfer between the microcontroller 180 and the fuel gauge IC 216.

In some embodiments, the microcontroller 180 is further configured to determine that the battery pack 20 is disconnected from the charger 10 upon not receiving the communication signals from the one or more battery communication lines 214 for a predetermined time period. With reference to FIG. 1A, the microcontroller 180 determines that the battery pack 20 is disconnected from the charger 10 upon not receiving the communication signals from the one or more battery communication lines 214 for the predetermined time period. In some embodiments, the predetermined time period may be selected or determined by the microcontroller 180.

In some embodiments, the microcontroller 180 is further configured to control the analog switch 150 to electrically disconnect the sense pin 108 from the charger sense line 116 until the battery pack 20 is sensed by the microcontroller 180. In some embodiments, the analog switch 150 is configured to electrically disconnect the sense pin 108 from the charger sense line 116 when the battery pack 20 is disconnected from the charger 10. With reference to FIG. 1A, the analog switch 150 electrically disconnects the sense pin 108 from the charger sense line 116 when the battery pack 20 is disconnected from the charger 10. Specifically, the microcontroller 180 controls the analog switch 150 to electrically disconnect the sense pin 108 from the charger sense line 116 when the battery pack 20 is disconnected from the charger 10, or until the battery pack 20 is sensed by the microcontroller 180.

In some embodiments, the analog switch 150 includes a first terminal 152 electrically connected to the sense pin 108 of the charger IC 102, a second terminal 154 electrically connected to the charger output line 112, and a third terminal 156 electrically connected to the charger sense line 116. In some embodiments, the analog switch 150 is configured to selectively connect the first terminal 152 to one of the second terminal 154 and the third terminal 156. In some embodiments, the analog switch 150 is further configured to electrically connect the first terminal 152 to the second terminal 154 when the battery pack 20 is disconnected from the charger 10. With reference to FIG. 1A, the analog switch 150 electrically connects the first terminal 152 to the second terminal 154 when the battery pack 20 is disconnected from the charger 10. In other words, when the battery pack 20 is disconnected from the charger 10, the sense pin 108 of the charger IC 102 may be electrically connected to the charger output line 112, via the first and second terminals 152, 154 of the analog switch 150. The analog switch 150 further includes a selection terminal 157. The switch state of the analog switch 150 can be selected or controlled by providing a signal at the selection terminal 157. The selection terminal 157 can be used to selectively connect the first terminal 152 to one of the second terminal 154 and the third terminal 156.

In the illustrated embodiment, the control line 181 electrically connects the selection terminal 157 of the analog switch 150 to the microcontroller 180. The microcontroller 180 can control or select the switch state of the analog switch 150 by providing control signals at the selection terminal 157. Specifically, the microcontroller 180 can selectively connect the first terminal 152 to one of the second terminal 154 and the third terminal 156 by applying control signals at the selection terminal 157 of the analog switch 150 via the control line 181.

In some embodiments, the charger 10 further includes an intermediate line 120 electrically connecting the second terminal 154 of the analog switch 150 to the charger output line 112. Therefore, when the battery pack 20 is disconnected from the charger 10, the sense pin 108 of the charger IC 102 is electrically connected to the charger output line 112, via the analog switch 150 and the intermediate line 120 of the charger 10.

When the battery pack 20 is not coupled to the charger 10, the electrical connection of the sense pin 108 and the charger output line 112, via the analog switch 150, may prevent an unregulated charger output voltage due to an otherwise open charger sense line 116. Therefore, upon disconnection of the battery pack 20 from the charger 10, the electrical connection of the sense pin 108 and the charger output line 112, via the analog switch 150, may prevent any damage to the charger IC 102 due to an otherwise open condition of the charger sense line 116 and the unregulated charger output voltage.

In some embodiments, the microcontroller 180 is further configured to sense the battery pack 20 upon receiving the communication signals from the one or more battery communication lines 214 via the one or more charger communication lines 182. In other words, the microcontroller 180 senses the battery pack 20 upon receiving the communication signals or the relevant data from the fuel gauge IC 216, via the battery and charger communication lines 214, 182. Therefore, when the microcontroller 180 receives the communication signals from the one or more battery communication lines 214 via the one or more charger communication lines 182, the microcontroller 180 determines that the battery pack 20 is coupled to the charger 10.

In some embodiments, upon receiving the communication signals from the one or more battery communication lines 214, the microcontroller 180 is further configured to control the analog switch 150 to electrically connect the sense pin 108 to the charger sense line 116 and activate the charger IC 102. In some embodiments, the analog switch 150 is configured to electrically connect the sense pin 108 of the charger IC 102 to the battery sense line 204 of the battery pack 20 upon sensing of the battery pack 20 by the charger 10. With reference to FIG. 1B, upon receiving the communication signals from the one or more battery communication lines 214, the microcontroller 180 controls the analog switch 150 to electrically connect the sense pin 108 to the battery sense line 204.

Referring to FIG. 1B, when the battery pack 20 is coupled to the charger 10, the battery input and sense lines 202, 204 are electrically connected to the charger output and sense lines 112, 116, respectively. In some embodiments, upon electrical connection of the battery input line 202 and the battery sense line 204 of the battery pack 20 to the charger output line 112 and the charger sense line 116, respectively, of the charger 10, the analog switch 150 is further configured to electrically connect the first terminal 152 to the third terminal 156. With reference to FIG. 1B, the to analog switch 150 electrically connects the first terminal 152 to the third terminal 156 upon electrical connection of the battery input line 202 and the battery sense line 204 to the charger output line 112 and the charger sense line 116, respectively. In other words, when the battery pack 20 is coupled to the charger 10, the sense pin 108 of the charger IC 102 is electrically connected to the battery sense line 204 of the battery pack 20, via the first and third terminals 152, 156 of the analog switch 150.

FIGS. 2A and 2B illustrate a charging system 200 according to another embodiment of the present disclosure. The charging system 200 is substantially similar to the charging system 100 illustrated in FIGS. 1A and 1B. Common components between the charging systems 100, 200 are illustrated by the same reference numerals. However, the charging system 200 includes a voltage regulator 50 electrically connected to the analog switch 150. In some embodiments, the charger 10 includes the voltage regulator 50 electrically connected to the analog switch 150. The voltage regulator 50 may be designed to maintain a constant output voltage level. The voltage regulator 50 may use an electromechanical mechanism, or electronic components.

In some embodiments, the voltage regulator 50 is a low dropout (LDO) voltage regulator 50. The LDO voltage regulator provides a stable power supply voltage independent of load impedance, input-voltage variations, temperature, and time. For the LDO voltage regulator 50, there is a small voltage drop between an input voltage and an output voltage. The LDO voltage regulator 50 provides a continuously controlled, steady, low-noise output voltage.

In some embodiments, the voltage regulator 50 is a switching voltage regulator. Generally, the switching voltage regulator is also referred to as DC-to-DC converter and used to provide a constant output voltage using an inductor as a means for energy storage. The switching voltage regulator typically provides power supply function through low loss components, such as capacitors, inductors, and transformers, and power switches that are turned on and off to transfer energy from an input to an output. In common applications, the switching voltage regulator can be used to step up the input voltage or step down the input voltage or both. Specifically, a buck switching regulator, also called a buck converter, steps down the input voltage while a boost switching regulator, also called a boost converter, steps up the input voltage. A buck-boost switching regulator, or buck-boost converter, provides both step-up and step-down functions.

In some embodiments, the voltage regulator 50 is electrically connected to the power source 23. Specifically, the voltage regulator 50 is electrically connected to the power supply line 110 that supplies electrical power from the power source 23 to the voltage regulator 50 as well as the input pin 104 of the charger IC 102.

Further, the voltage regulator 50 is electrically connected to the microcontroller 180. In some embodiments, the analog switch 150 is further configured to electrically connect the voltage regulator 50 to the charger sense line 116 until the battery pack 20 is sensed by the charger 10. With reference to FIG. 2A, the analog switch 150 electrically connects the voltage regulator 50 to the charger sense line 116 when the battery pack 20 is disconnected from the charger 10. Moreover, in some embodiments, the microcontroller 180 is further configured to control the analog switch 150 to electrically connect the voltage regulator 50 to the charger sense line 116 until the battery pack 20 is sensed by the microcontroller 180. With reference to FIG. 2A, the microcontroller 180 controls the analog switch 150 to electrically connect the voltage regulator 50 to the charger sense line 116 until the battery pack 20 is sensed by the microcontroller 180.

In the illustrated embodiment of FIGS. 2A and 2B, the voltage regulator 50 includes an input 51, an output 52, and a control 53. The input 51 of the voltage regulator 50 is electrically connected to the power supply 110. The output 52 of the voltage regulator 50 is electrically connected to the second terminal 154 of the analog switch 150. The control 53 of the voltage regulator 50 is electrically connected to the microcontroller 180. The voltage regulator 50 may provide a regulated voltage “Vr” at the output 52 based on an input voltage received at the input 51. Further, the microcontroller 180 may activate or deactivate the voltage regulator 50 by providing a control signal at the control 53 of the voltage regulator 50. Further, the microcontroller 180 may control the voltage regulator 50 via the control 53. For example, the microcontroller 180 may regulate the regulated voltage “Vr” via the control 53.

In some embodiments, the analog switch 150 includes the first terminal 152 electrically connected to the sense pin 108 of the charger IC 102, the second terminal 154 electrically connected to the voltage regulator 50, and the third terminal 156 electrically connected to the charger sense line 116. In some embodiments, the analog switch 150 is configured to selectively connect the third terminal 156 to one of the first terminal 152 and the second terminal 154. With reference to FIG. 2A, the analog switch 150 is further configured to electrically connect the second terminal 154 to the third terminal 156 until the battery pack 20 is sensed by the charger 10. In some embodiments, the microcontroller 180 is further configured to control the analog switch 150 to electrically connect the second terminal 154 to the third terminal 156 until the battery pack 20 is sensed by the microcontroller 180. Therefore, the microcontroller 180 controls the analog switch 150 to electrically connect the second terminal 154 to the third terminal 156 when the battery pack 20 is electrically disconnected from the charger 10.

With reference to FIG. 2B, the analog switch 150 is further configured to electrically connect the first terminal 152 to the third terminal 156 upon sensing of the battery pack 20 by the charger 10. In some embodiments, the microcontroller 180 is further configured to control the analog switch 150 to electrically connect the first terminal 152 to the third terminal 156 upon sensing of the battery pack 20 by the microcontroller 180. Therefore, the microcontroller 180 controls the analog switch 150 to electrically connect the first terminal 152 to the third terminal 156 when the battery pack 20 is electrically coupled to the charger 10.

In some embodiments, the first terminal 152 and the second terminal 154 may correspond to input terminals of the analog switch 150, while the third terminal 156 may correspond to an output terminal of the analog switch 150. At a given time, the output terminal is selectively connected to one of the input terminals.

In some embodiments, the voltage regulator 50 is further configured to output the regulated voltage “Vr” to the charger sense line 116 when the voltage regulator 50 is electrically connected to the charger sense line 116. With reference to FIG. 2A, the voltage regulator 50 outputs the regulated voltage “Vr” to the charger sense line 116 when the second terminal 154 is electrically connected to the third terminal 156. Further, the voltage regulator 50 is electrically connected to the charger sense line 116 via the second and third terminals 154, 156.

Upon coupling of the battery pack 20 to the charger 10, the regulated voltage “Vr” is fed to the battery sense line 204 from the charger sense line 116. In other words, upon electrical connection of the battery input line 202 and the battery sense line 204 of the battery pack 20 to the charger output line 112 and the charger sense line 116, respectively, the regulated voltage “Vr” is fed to the charger and battery sense lines 116, 204. For the battery pack 20 in the inactive state, the fuel gauge IC 216 does not output the communication signals. In some embodiments, the voltage regulator 50 is configured to switch the battery pack 20 from the inactive state to the active state via the regulated voltage “Vr” provided to the battery sense line 204. The regulated voltage “Vr” is applied on the battery sense line 204, such that the fuel gauge IC 216 can detect the regulated voltage “Vr” at the node 207. In some cases, the regulated voltage “Vr” may activate the battery pack 20. For example, upon coupling the battery pack 20 in an inactive or a dead battery condition to the charger 10, charging of the battery pack 20 may not be initialized as the fuel gauge IC 216 may be in switched off and unable to output the communication signals to the microcontroller 180 of the charger 10. In such cases, the regulated voltage “Vr” from the voltage regulator 50 may be applied at the node 207 in order to switch on the fuel gauge IC 216 so that the battery pack 20 can be sensed by the microcontroller 180 and charging of the battery pack 20 can be initiated. Further, the battery sense line 204 provides a low impedance path to the regulated voltage “Vr” bypassing the at least one blocking device 208. Therefore, a relative low value of the regulated voltage “Vr” may be sufficient to activate the battery pack 20. In some embodiments, the microcontroller 180 may switch off or deactivate the voltage regulator 50 upon sensing the battery pack 20.

In some examples, when the battery pack 20 in the dead battery condition is coupled to the charger 10, the fuel gauge IC 216 does not output the communication signals to the microcontroller 180 via the battery and charger communication lines 214, 182. While the battery pack 20 is in the dead battery condition and coupled to the charger 10, the microcontroller 180 may not activate the charger IC 102, and the sense pin 108 may not be electrically connected to the charger sense line 116. While the charger IC 102 is not activated, the voltage regulator 50 may be electrically connected to the charger sense line 116. Thus, upon connecting the battery pack 20 in the dead battery condition with the charger 10, the voltage regulator 50 may provide the regulated voltage “Vr” at a low current to the charger and battery sense lines 116, 204, to incrementally charge the electrochemical cells 206 and activate the battery pack 20 in the dead battery condition. Therefore, the charging system 200 including the voltage regulator 50 and the analog switch 150 may be used to wake up or activate the battery pack 20 in the dead battery condition when coupled to the charger 10. In other words, for the battery pack 20 coupled to the charger 10 in the dead battery condition, the voltage regulator 50 may provide a reviving voltage, via the battery sense line 204, to activate the battery pack 20.

Once the battery pack 20 is activated, the battery pack 20 may be switched from the inactive state to the active state. Therefore, the fuel gauge IC 216 may start outputting the communication signals to the microcontroller 180 via the battery communication lines 214. Upon receiving the communication signals from the battery communication lines 214, via the charger communication lines 182, the microcontroller 180 may sense the battery pack 20. Upon sensing of the battery pack 20 by the microcontroller 180, the microcontroller 180 may activate the charger IC 102 of the charger 10. Further, upon sensing of the battery pack 20 by the microcontroller 180, the microcontroller 180 may control the analog switch 150 to electrically disconnect the third terminal 156 and the second terminal 154, and electrically connect the third terminal 156 to the first terminal 152. The charger IC 102 may provide the output voltage “Vo”, via the charger output line 112, to the battery input line 202 to supply power for recharging the electrochemical cells 206 in the battery pack 20. With reference to FIG. 2B, the voltage regulator 50 is electrically disconnected from the charger sense line 116, and the sense pin 108 of the charger IC 102 is electrically connected to the charger sense line 116.

Therefore, the voltage regulator 50 may enable the charger 10 to activate, detect and charge the battery pack 20 whose safety switch (not shown in FIGS. 2A and 2B) is engaged due to a prior faulty condition and is initially in an inactive state.

FIGS. 3A and 3B illustrate a charging system 300 according to another embodiment of the present disclosure. The charging system 300 is substantially similar to the charging system 200 illustrated in FIGS. 2A and 2B. Common components between the charging systems 200, 300 are illustrated by the same reference numerals. However, in the charging system 300, the battery pack 20 further includes a cell ground