3 and the feedback control circuit 5 respectively, and is used to generate the switch off control command S3 and the switch on control command S4 according to the normal operation signal S1 and the energy-saving operation signal S2 respectively, and is used to generate the positive voltage control command S5 and the additional voltage control command S6 according to the feedback control signal S7.

The switch drive circuit 42 is electrically connected to the switch logic control circuit 41, the energy-saving switch 2 and the inductance control switches SW1 to SW4 respectively, and is used to drive the energy-saving switch 2 to turn off or on according to the switch off control command S3 and the switch on control command S4, and is used to drive the inductor control switches SW1 to SW4 to turn off or on according to the positive voltage control command S5 and the additional voltage control command S6.

In this embodiment, the feedback control circuit 5 includes a current detector 51, a ramp signal generator 52, a voltage divider resistor circuit 53, an error amplifier 54, an adder 55 and a comparator circuit 56. The current detector 51 is electrically connected to the inductor L and the switching logic control circuit 41 respectively, and is used to generate an inductor current detector output voltage Vdi when the inductor current IL is detected to be 0.

The ramp signal generator 52 is electrically connected to the inductor L and the comparator circuit 56 respectively, and includes a signal converter 521, a frequency generator 522 and an adder 523. In this embodiment, the ramp signal generator 52 converts the inductor current IL into a voltage signal through the signal converter 521, and then adds the voltage signal to a fixed frequency signal generated by the frequency generator 522 through the adder 523 to generate a ramp voltage Vramp.

The voltage divider resistor circuit 53 is electrically connected to the positive voltage output source 300, the additional voltage output source 301 and the error amplifier 54 respectively, and is used to convert the output positive voltage Vop and the additional output voltage Von into a feedback positive voltage Vpfb and a feedback negative voltage Vnfb respectively by using the internal resistor voltage divider. The error amplifier 54 is electrically connected to the voltage dividing resistor circuit 53, the adder 55 and the comparator circuit 56 respectively, and is used to convert the feedback positive voltage Vpfb into a positive operation voltage Vpo, and to convert the feedback negative voltage Vnfb into a negative operation voltage Vno.

The adder 55 is electrically connected to the error amplifier 54 and the comparator circuit 56 respectively, and is used to add the positive operation voltage Vpo and the negative operation voltage Vno to obtain an operation difference voltage Vpno. The comparator circuit 56 is electrically connected to the switch logic control circuit 41, the ramp signal generator 52, the error amplifier 54 and the adder 55, and includes three comparators 561 to 563.

The comparator 561 is used to generate a comparative positive voltage Vpc when the ramp voltage Vramp is greater than or equal to the operation positive voltage Vpo. The comparator 562 is used to generate a comparative difference voltage Vpnc when the ramp voltage Vramp is greater than or equal to the operation difference voltage Vpno. The comparator 563 is used to generate a comparative negative voltage Vnc when the ramp voltage Vramp is greater than or equal to the operation negative voltage Vno.

In summary, the feedback control circuit 5 generates the comparative positive voltage Vpc, the comparative difference voltage Vpnc and the comparative negative voltage Vnc by monitoring and controlling the inductor L, the positive voltage output source 300 and the additional voltage output source 301, and the feedback control circuit 5 sends the comparative positive voltage Vpc, the comparative difference voltage Vpnc and the comparative negative voltage Vnc to the switch logic control circuit 41 as the feedback control signal S7. The structures and working principles of the above mentioned current detector 51, ramp signal generator 52, voltage divider resistor circuit 53, error amplifier 54, adder 55 and comparator circuit 56 are all prior art and are not claimed by the present invention, so they will not be described again in this embodiment.

Referring to the FIGS. 4 to 6, the FIG. 4 illustrates the switch control sequence diagram of the single inductor multiple output converter with energy-saving operation mode provided by the present invention in the normal operation mode; the FIG. 5 illustrates the inductor current and slope voltage waveforms in normal operation mode of the single inductor multiple output converter with energy-saving operation mode provided by the present invention; and, the FIG. 6 illustrates the input and output voltage waveforms of the single inductor multiple output converter with energy-saving operation mode provided by the present invention in normal operation mode.

As shown in the FIGS. 4 to 6, in the normal operating mode, that is, when the input voltage Vin is less than the output positive voltage Vop, the energy-saving switch 2 remains turned off.

At this time, the inductor control switches SW1 to SW4 are controlled by the positive voltage control command S5 and the additional voltage control command S6, and are turned on or off to repeatedly charge and discharge the inductor L, thereby converting the input voltage Vin into the output positive voltage Vop and the additional output voltage Von. The positive voltage control command S5 includes a plurality of positive voltage control subcommands arranged according to a positive voltage control sequence. The additional voltage control command S6 includes a plurality of additional voltage control subcommands arranged according to an additional voltage control sequence.

In this embodiment, both the positive voltage control sequence and the additional voltage control sequence use four phases SP1 to SP4 as one control cycle to control the inductor control switches SW1 to SW4. In other words, the positive voltage control command S5 includes the first positive voltage control subcommand, the second positive voltage control subcommand, the third positive voltage control subcommand and the fourth positive voltage control subcommand, and corresponds to the four phases SP1 to SP4 respectively. The additional voltage control command S6 includes a first additional voltage control subcommand, a second additional voltage control subcommand, a third additional voltage control subcommand, and a fourth additional voltage control subcommand, and corresponds to the four phases SP1 to SP4 respectively. In addition, in this embodiment, the positive voltage control command S5 is used to control the inductor control switches SW2 and SW3, and the additional voltage control command S6 is used to control the inductor control switches SW