A power supply with a wide output voltage range and a control method thereof

Abstract

The present invention provides a power supply with a wide output voltage range, comprising a front-stage conversion circuit and a rear-stage conversion circuit. The front-stage conversion circuit outputs a first voltage, and the rear-stage conversion circuit receives the first voltage as input and converts it into a second voltage for output. The first voltage varies from a first set value to an upper limit of the rated output voltage of the power supply, or from the first set value to a lower limit of the rated output voltage of the power supply. The present invention uses two-stage circuits to process different output voltage ranges, thereby enabling the circuit to support a wider operating voltage range with a smaller duty cycle variation range, thereby reducing the impact of output voltage variation on efficiency.

Description

Technical Field

[0001] The invention belongs to the technical field of electric energy conversion and relates to a circuit output voltage regulation technology. Background Art

[0002] A single-stage power conversion circuit, such as a Flyback circuit, changes the reference value of the circuit feedback to change the duty cycle of the single-stage power conversion circuit during operation, thereby adjusting the output voltage of the single-stage power conversion circuit within a certain range.

[0003] However, if the output voltage range is increased, for example, to 5V-48V, the duty cycle of the single-stage power conversion circuit will need to vary over a wider range. This will result in the single-stage power conversion circuit having to use a very small duty cycle at lower output voltages, resulting in low efficiency at low voltage outputs.

[0004] In some situations where a single-stage output is impractical, such as when multiple outputs are required or when Flyback is unsuitable, a two-stage power conversion circuit is used. The first-stage power conversion circuit outputs a fixed voltage, typically 20V. The second-stage power conversion circuit typically uses a buck circuit to step down the voltage to 5V-20V. In situations where multiple outputs are required, multiple buck circuits are used.

[0005] Since the output voltage of the first-stage power conversion circuit is fixed, the power conversion circuit must still use a very small duty cycle when the output voltage is relatively low, resulting in low efficiency of the power conversion circuit when the output voltage is low. Summary of the Invention

[0006] To achieve the above-mentioned and other related purposes, the present invention provides a power supply with a wide output voltage range, comprising:

[0007] The front-stage conversion circuit outputs a first voltage.

[0008] The post-stage conversion circuit receives the first voltage input and converts it into a second voltage output, wherein the first voltage varies from a first set value to a maximum value of the second voltage and is not less than a minimum value of the second voltage.

[0009] The above-mentioned power supply with a wide output voltage range also includes a control circuit, which accepts a second voltage reference value and compares the second voltage reference value with a first set value. When the second voltage reference value is greater than the first set value, the first voltage output by the front-stage conversion circuit is adjusted according to the second voltage reference value, and the rear-stage conversion circuit does not adjust the first voltage; when the second voltage reference value is not greater than the first set value, the front-stage conversion circuit outputs the minimum value of the first voltage, and the second voltage output by the rear-stage conversion circuit is adjusted according to the second voltage reference value.

[0010] When the latter-stage conversion circuit does not adjust the first voltage, the control circuit controls the latter-stage conversion circuit to be directly turned on.

[0011] The above-mentioned control circuit includes a first comparator, a second comparator and a third comparator. The first comparator compares a reference value of the second voltage with a first set value. When the second voltage reference value is greater than the first set value, the second comparator compares the second voltage reference value with a sampled value of the first voltage and controls the first voltage to follow the reference value of the second voltage. The third comparator compares the maximum value of the second voltage with the sampled value of the second voltage and controls the second voltage to follow the maximum value of the second voltage. When the second voltage reference value is not greater than the first set value, the second comparator compares the minimum value of the first voltage with the sampled value of the first voltage and controls the first voltage to follow the minimum value of the first voltage. The third comparator compares the reference value of the second voltage with the sampled value of the second voltage and controls the second voltage to follow the reference value of the second voltage.

[0012] The above-mentioned control circuit also includes a front-stage driving unit and a rear-stage driving unit. The front-stage driving unit generates a driving signal for driving the switching device in the front-stage conversion circuit according to the output signal of the second comparator, and the rear-stage driving unit generates a driving signal for driving the switching device in the rear-stage conversion circuit according to the output signal of the third comparator.

[0013] The above-mentioned front-stage conversion circuit is an isolated conversion circuit, and the latter-stage conversion circuit is a non-isolated step-down conversion circuit.

[0014] The present invention provides another power supply with a wide output voltage range, comprising:

[0015] The front-stage conversion circuit outputs a first voltage.

[0016] The post-stage conversion circuit receives the first voltage input and converts it into a second voltage output, wherein the first voltage varies from a minimum value of the second voltage to a second set value and is not greater than a maximum value of the second voltage.

[0017] The above-mentioned power supply with a wide output voltage range also includes a control circuit, which accepts a second voltage reference value and compares the second voltage reference value with a second set value. When the second voltage reference value is less than the second set value, the first voltage output by the front-stage conversion circuit changes according to the second voltage reference value, and the rear-stage conversion circuit does not adjust the first voltage. When the second voltage reference value is not less than the second set value, the front-stage conversion circuit outputs the maximum value of the first voltage, and the rear-stage conversion circuit adjusts the first voltage according to the second voltage reference value.

[0018] When the latter-stage conversion circuit does not adjust the first voltage, the control circuit controls the latter-stage conversion circuit to be directly turned on.

[0019] The above-mentioned control circuit includes a first comparator, a second comparator and a third comparator. The first comparator compares a reference value of the second voltage with a first set value. When the second voltage reference value is less than the first set value, the second comparator compares the second voltage reference value with a sampled value of the first voltage and controls the first voltage to follow the reference value of the second voltage. The third comparator compares the minimum value of the second voltage with the sampled value of the second voltage and controls the second voltage to follow the maximum value of the second voltage. When the second voltage reference value is not less than the first set value, the second comparator compares the maximum value of the first voltage with the sampled value of the first voltage and controls the first voltage to follow the maximum value of the first voltage. The third comparator compares the reference value of the second voltage with the sampled value of the second voltage and controls the second voltage to follow the reference value of the second voltage.

[0020] The above-mentioned control circuit also includes a front-stage driving unit and a rear-stage driving unit. The front-stage driving unit generates a driving signal for driving the switching device in the front-stage conversion circuit according to the output signal of the second comparator, and the rear-stage driving unit generates a driving signal for driving the switching device in the rear-stage conversion circuit according to the output signal of the third comparator.

[0021] The front-stage conversion circuit is an isolated conversion circuit, and the rear-stage conversion circuit is a non-isolated boost conversion circuit.

[0022] A power supply control method with a wide output voltage range of the present invention includes:

[0023] A front-stage conversion circuit and a rear-stage conversion circuit are provided, wherein the front-stage conversion circuit outputs a first voltage, and the rear-stage conversion circuit adjusts the first voltage to convert it into a second voltage.

[0024] Accepting a second voltage reference value, when the second voltage reference value is less than a first set value, controlling the front-stage conversion circuit to output the minimum value of the first voltage, and then controlling the rear-stage conversion circuit to adjust the second voltage to follow the change of the second voltage reference value; when the second voltage reference value is not less than the first set value, controlling the front-stage conversion circuit to adjust the first voltage to follow the change of the second voltage reference value, and controlling the rear-stage conversion circuit to be in a direct-through state or a state of its maximum working duty cycle.

[0025] Another power supply control method with a wide output voltage range of the present invention includes:

[0026] A front-stage conversion circuit and a rear-stage conversion circuit are provided, wherein the front-stage conversion circuit outputs a first voltage, and the rear-stage conversion circuit adjusts the first voltage to convert it into a second voltage.

[0027] Accepting a second voltage reference value, when the second voltage reference value is greater than a second set value, controlling the front-stage conversion circuit to output the maximum value of the first voltage, and then controlling the rear-stage conversion circuit to adjust the second voltage to follow the change of the second voltage reference value; when the second voltage reference value is not greater than the second set value, controlling the front-stage conversion circuit to adjust the first voltage to follow the change of the second voltage reference value, and controlling the rear-stage conversion circuit to be in a direct-through state or a state of its maximum working duty cycle.

[0028] The present invention uses two-stage circuits to process different output voltage ranges respectively, so that the circuit can support a wider operating voltage range with a smaller duty cycle variation range, reducing the impact of output voltage variation on efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 Shown is a block diagram of a first embodiment of a power supply according to the present invention.

[0030] Figure 2 Shown is a block diagram of a second embodiment of the power supply of the present invention.

[0031] Figure 3 The first embodiment of the control circuit of the present invention is shown.

[0032] Figure 4 The second embodiment of the control circuit of the present invention is shown.

[0033] Figure 5 Shown is a schematic diagram of a first specific implementation of a first embodiment of the power supply of the present invention.

[0034] Figure 6 Shown is a schematic diagram of a second specific implementation of the first embodiment of the power supply of the present invention.

[0035] Figure 7Shown is a schematic diagram of a third specific implementation of the first embodiment of the power supply of the present invention.

[0036] Figure 8 Shown is a flow chart of a first embodiment of the control method of the present invention.

[0037] Figure 9 Shown is a flow chart of a second embodiment of the control method of the present invention. DETAILED DESCRIPTION

[0038] The following describes the implementation of the present invention through specific embodiments. Those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification.

[0039] It should be noted that the drawings in this specification are only used to match the contents disclosed in the specification for those skilled in the art to understand and read, and are not used to limit the conditions under which the present invention can be implemented, and therefore have no substantive technical significance.

[0040] Figure 1 The figure shows a block diagram of an embodiment of a power supply of the present invention. The power supply 10 includes a front-stage conversion circuit 11 and a rear-stage conversion circuit 12. The front-stage conversion circuit 11 converts, for example, AC power or DC power into a voltage Vt output, and the rear-stage conversion circuit 12 converts the voltage Vt into a voltage Vo and provides it to a load 13.

[0041] In a preferred embodiment of the present invention, the voltage Vt is variable, and the range of the voltage Vt is from a first set value Vm1 to the maximum value Vomax of the rated output voltage of the power supply 10, and is not less than the minimum value Vomin of the output voltage of the power supply 10. The front-stage conversion circuit 11 has an isolation function, and the rear-stage conversion circuit 12 is a non-isolated step-down circuit, such as a BUCK conversion circuit. Please refer to Figure 5 , the front stage conversion circuit 51 is an LLC resonant circuit, and the rear stage conversion circuit 52 is a BUCK circuit. Figure 6 The front-stage conversion circuit 61 is an asymmetric half-bridge flyback topology structure, and the rear-stage conversion circuit 62 is a BUCK circuit.

[0042] In another preferred embodiment of the present invention, the voltage Vt is variable, and the range of the voltage Vt is from the minimum value Vomin of the rated output voltage of the power supply 10 to the second set value Vm2, and is not greater than the maximum value Vomax of the output voltage of the power supply 10. The front-stage conversion circuit 11 has an isolation function. The rear-stage conversion circuit 12 is a non-isolated boost circuit, such as a BOOST conversion circuit. Please refer to Figure 7 The front-stage conversion circuit 71 is an LLC resonant circuit, and the rear-stage conversion circuit 72 is a BOOST circuit.

[0043] The control circuit 14 has a communication function with the outside of the power supply 10, accepts the output voltage reference value Vo_ref input from the outside, and is coupled with the front-stage conversion circuit 11 and the rear-stage conversion circuit 12 to detect the voltage Vt and the voltage Vo, and provide control signals for the front-stage conversion circuit 11 and the rear-stage conversion circuit 12, such as controlling the operating frequency or duty cycle of the switching devices in the front-stage conversion circuit 11 and the rear-stage conversion circuit 12, thereby controlling the voltage Vt and the voltage Vo.

[0044] In one embodiment of the present invention, when the control circuit 14 receives the output voltage reference value Vo_ref and the output voltage reference value Vo_ref is less than the first set value Vm1, the control circuit 14 controls the front-stage conversion circuit 11 to output its minimum output voltage Vtmin, and then controls the back-stage conversion circuit 12 to output the voltage Vo that meets the requirements of the signal Vo_ref; when the control circuit 14 receives the output voltage reference value Vo_ref and the output voltage reference value Vo_ref is not less than the first set value Vm1, the control circuit 14 controls the front-stage conversion circuit 11 to output the voltage Vt that meets the requirements of the output voltage reference value Vo_ref, and controls the back-stage conversion circuit 12 to be in a direct-on state or a state of its maximum working duty cycle, without adjusting the voltage Vt. Preferably, the voltage Vt-Vc=Vo, where Vc is a fixed voltage used to compensate for the voltage drop of the back-stage conversion circuit 12, so that after the front-stage conversion circuit 11 outputs the voltage Vt, the output of the back-stage conversion circuit 12 is the voltage Vo that meets the requirements.

[0045] Please refer to Figure 3 Schematic diagram of an embodiment of a control circuit 34. The control circuit 34 includes comparators U1, U2, and U3. The output end of the comparator U1 is used to control a selection unit 343 and a selection unit 344. The selection units 343 and 344 control the reference values ​​of the comparators U2 and U3. The comparator U1 compares the reference value Vo_ref of the output voltage with a first set value Vm1. When the reference value Vo_ref of the output voltage is greater than the first set value Vm1, the selection unit 343 selects the reference value Vo_ref of the output voltage, and the selection unit 344 selects the maximum value Vomax of the output voltage. The comparator U2 compares the reference value Vo_ref of the output voltage with the sampled value of the voltage Vt and controls the voltage Vt to follow the change of the reference value Vo_ref of the output voltage. The comparator U3 compares the maximum value Vomax of the output voltage with the sampled value of the output voltage Vo and controls the change of the output voltage Vo to follow the maximum value Vomax of the output voltage.

[0046] When the reference value Vo_ref of the output voltage is not greater than the first set value Vm1, the selection unit 343 selects the minimum voltage Vtmin output by the previous stage conversion circuit, the selection unit 344 selects the reference value Vo_ref of the output voltage, the comparator U2 compares the minimum voltage Vtmin output by the previous stage conversion circuit with the sampling value of the voltage Vt, and controls the voltage Vt to follow the change of the voltage Vtmin, the comparator U3 compares the reference value Vo_ref of the output voltage with the sampling value of the output voltage Vo, and controls the output voltage Vo to follow the change of the reference value Vo_ref of the output voltage.

[0047] The control circuit 34 also includes a front-stage driving unit 341 and a rear-stage driving unit 342. The front-stage driving unit 341 generates a driving signal for driving the switching device in the front-stage conversion circuit according to the output signal of the comparator U2, and the rear-stage driving unit 342 generates a driving signal for driving the switching device in the rear-stage conversion circuit according to the output signal of the comparator U3.

[0048] refer to Figure 5 The topology of the front-stage conversion circuit 51 is an LLC resonant conversion circuit, and the topology of the rear-stage conversion circuit 52 is a BUCK circuit.

[0049] In another embodiment of the present invention, When the control circuit 14 receives the output voltage reference value Vo_ref and the output voltage reference value Vo_ref is not greater than the second set value Vm2, the control circuit 14 controls the front-stage conversion circuit 11 to output the voltage Vo that meets the requirements of the output voltage reference value Vo_ref, and then controls the rear-stage conversion circuit 12 to be in a direct-through state or a state of its maximum working duty cycle, and does not adjust the voltage Vt; when the control circuit 14 receives the output voltage reference value Vo_ref and the output voltage reference value Vo_ref is greater than the second set value Vm2, the control circuit 14 controls the front-stage conversion circuit 11 to output its maximum output voltage Vtmax, and then controls the rear-stage conversion circuit 12 to output the voltage Vo that meets the requirements of the output voltage reference value Vo_ref.

[0050] like Figure 4FIG. 4 is a schematic diagram of an embodiment of a control circuit 44 according to the present invention. The control circuit 44 includes comparators U1, U2, and U3. The output of comparator U1 is connected to a selection unit 443 and a selection unit 444. Selection units 443 and 444 control the reference values ​​of comparators U2 and U3. Comparator U1 compares the reference value Vo_ref of the output voltage with a second set value Vm2. When the reference value Vo_ref of the output voltage is less than the second set value Vm2, selection unit 443 selects the reference value Vo_ref of the output voltage, and selection unit 444 selects the minimum value Vomin of the output voltage. Comparator U2 compares the reference value Vo_ref of the output voltage with the sampled value of the voltage Vt and controls the voltage Vt to follow the reference value Vo_ref of the output voltage. Comparator U3 compares the minimum value Vomin of the output voltage with the sampled value of the output voltage Vo and controls the output voltage Vo to follow the maximum value Vomin of the output voltage.

[0051] When the reference value Vo_ref of the output voltage is not less than the first set value Vm1, the selection unit 443 selects the front-stage conversion circuit to output the maximum voltage Vtmax that it can output, the selection unit 444 selects the reference value Vo_ref of the output voltage, the comparator U2 compares the maximum voltage Vtmax that the front-stage conversion circuit can output and the sampling value of the voltage Vt, and controls the voltage Vt to follow the change of the voltage Vtmax, the comparator U3 compares the reference value Vo_ref of the output voltage and the sampling value of the output voltage Vo, and controls the output voltage Vo to follow the change of the reference value Vo_ref of the output voltage.

[0052] The control circuit 44 also includes a front-stage driving unit 441 and a rear-stage driving unit 442. The front-stage driving unit 441 generates a driving signal for driving the switching device in the front-stage conversion circuit according to the output signal of the comparator U2, and the rear-stage driving unit 442 generates a driving signal for driving the switching device in the rear-stage conversion circuit according to the output signal of the comparator U3.

[0053] refer to Figure 7 The topology of the front-stage conversion circuit 71 is an LLC resonant conversion circuit, and the topology of the rear-stage conversion circuit 72 is a BOOST circuit.

[0054] Figure 2 Another embodiment of the present invention is shown. Figure 1The difference is that in this embodiment, a switch S1 is connected in series between the subsequent conversion circuit 22 and the load 23. The switch S1 can be a mechanical switch or a semiconductor switch, such as a MOSFET, which is used to connect or disconnect the connection between the subsequent conversion circuit 22 and the load 23.

[0055] The load is connected to the power supply 10 or 20 via a USB Type A or USB Type C port.

[0056] Figure 8 As shown, a power supply control method with a wide output voltage range of the present invention includes:

[0057] Step 81 sets a front-stage conversion circuit and a rear-stage conversion circuit, wherein the front-stage conversion circuit outputs a first voltage, and the rear-stage conversion circuit adjusts the first voltage to convert it into a second voltage.

[0058] Step 82 receives a second voltage reference value.

[0059] In step 83, when the second voltage reference value is less than the first set value, the front-stage conversion circuit is controlled to output the minimum value of the first voltage, and then the rear-stage conversion circuit is controlled to adjust the second voltage to follow the change of the second voltage reference value.

[0060] In step 84, when the second voltage reference value is not less than the first set value, the front-stage conversion circuit is controlled to adjust the first voltage to follow the change of the second voltage reference value, and the rear-stage conversion circuit is controlled to be in a direct-through state or a state of its maximum working duty cycle.

[0061] Figure 9 As shown, another power supply control method with a wide output voltage range of the present invention includes:

[0062] Step S91 sets a front-stage conversion circuit and a rear-stage conversion circuit, wherein the front-stage conversion circuit outputs a first voltage, and the rear-stage conversion circuit adjusts the first voltage to be converted into a second voltage.

[0063] Step S92 receives the second voltage reference value.

[0064] In step S93, when the second voltage reference value is greater than the second set value, the front-stage conversion circuit is controlled to output the maximum value of the first voltage, and then the rear-stage conversion circuit is controlled to adjust the second voltage to follow the change of the second voltage reference value.

[0065] In step S94, when the second voltage reference value is not greater than the second set value, the front-stage conversion circuit is controlled to adjust the first voltage to follow the change of the second voltage reference value, and the rear-stage conversion circuit is controlled to be in a direct-through state or a state of its maximum working duty cycle.

[0066] In summary, a hybrid control method is used to process different output voltage ranges using two-stage circuits, so that the circuit can support a wider operating voltage range with a smaller duty cycle variation range, reducing the impact of output voltage variation on efficiency.

[0067] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the present invention. Anyone skilled in the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by one of ordinary skill in the art without departing from the spirit and technical principles disclosed herein are intended to be covered by the claims of the present invention.

Claims

1. A power supply with a wide output voltage range, characterized in that: include, The front stage conversion circuit outputs a first voltage, a post-stage conversion circuit, receiving an input of the first voltage and converting it into a second voltage for output, wherein the first voltage varies from a first set value to a maximum value of the second voltage and is not less than a minimum value of the second voltage; It also includes a control circuit, which receives a second voltage reference value and compares the second voltage reference value with a first set value. When the second voltage reference value is greater than the first set value, the first voltage output by the front-stage conversion circuit is adjusted according to the second voltage reference value, and the rear-stage conversion circuit does not adjust the first voltage; when the second voltage reference value is not greater than the first set value, the front-stage conversion circuit outputs the minimum value of the first voltage, and the second voltage output by the rear-stage conversion circuit is adjusted according to the second voltage reference value.

2. A power supply with a wide output voltage range as claimed in claim 1, characterized in that: When the subsequent stage conversion circuit does not adjust the first voltage, the control circuit controls the subsequent stage conversion circuit to be directly turned on.

3. A power supply with a wide output voltage range as claimed in claim 1, characterized in that: The control circuit includes a first comparator, a second comparator and a third comparator. The first comparator compares a reference value of the second voltage with a first set value. When the second voltage reference value is greater than the first set value, the second comparator compares the second voltage reference value with a sampled value of the first voltage and controls the first voltage to follow the reference value of the second voltage. The third comparator compares the maximum value of the second voltage with the sampled value of the second voltage and controls the second voltage to follow the maximum value of the second voltage. When the second voltage reference value is not greater than the first set value, the second comparator compares the minimum value of the first voltage with the sampled value of the first voltage and controls the first voltage to follow the minimum value of the first voltage. The third comparator compares the reference value of the second voltage with the sampled value of the second voltage and controls the second voltage to follow the reference value of the second voltage.

4. A power supply with a wide output voltage range as claimed in claim 3, characterized in that: The control circuit also includes a front-stage driving unit and a rear-stage driving unit. The front-stage driving unit generates a driving signal for driving the switching device in the front-stage conversion circuit according to the output signal of the second comparator, and the rear-stage driving unit generates a driving signal for driving the switching device in the rear-stage conversion circuit according to the output signal of the third comparator.

5. A power supply with a wide output voltage range as claimed in claim 4, characterized in that: The front-stage conversion circuit is an isolated conversion circuit, and the rear-stage conversion circuit is a non-isolated step-down conversion circuit.

6. A power supply with a wide output voltage range, characterized in that: include, The front stage conversion circuit outputs a first voltage, a post-stage conversion circuit, receiving an input of the first voltage and converting it into a second voltage for output, wherein the first voltage varies from a minimum value of the second voltage to a second set value and is not greater than a maximum value of the second voltage; It also includes a control circuit, which receives a second voltage reference value and compares the second voltage reference value with a second set value. When the second voltage reference value is less than the second set value, the first voltage output by the front-stage conversion circuit changes according to the second voltage reference value, and the rear-stage conversion circuit does not adjust the first voltage. When the second voltage reference value is not less than the second set value, the front-stage conversion circuit outputs the maximum value of the first voltage, and the rear-stage conversion circuit adjusts the first voltage according to the second voltage reference value.

7. A power supply with a wide output voltage range as claimed in claim 6, characterized in that: When the subsequent stage conversion circuit does not adjust the first voltage, the control circuit controls the subsequent stage conversion circuit to be directly turned on.

8. A power supply with a wide output voltage range as claimed in claim 7, characterized in that: The control circuit includes a first comparator, a second comparator and a third comparator. The first comparator compares a reference value of a second voltage with a first set value. When the second voltage reference value is less than the first set value, the second comparator compares the second voltage reference value with a sampled value of the first voltage and controls the first voltage to follow the reference value of the second voltage. The third comparator compares the minimum value of the second voltage with the sampled value of the second voltage and controls the second voltage to follow the maximum value of the second voltage. When the second voltage reference value is not less than the first set value, the second comparator compares the maximum value of the first voltage with the sampled value of the first voltage and controls the first voltage to follow the maximum value of the first voltage. The third comparator compares the reference value of the second voltage with the sampled value of the second voltage and controls the second voltage to follow the reference value of the second voltage.

9. A power supply with a wide output voltage range as claimed in claim 8, characterized in that: The control circuit also includes a front-stage driving unit and a rear-stage driving unit. The front-stage driving unit generates a driving signal for driving the switching device in the front-stage conversion circuit according to the output signal of the second comparator, and the rear-stage driving unit generates a driving signal for driving the switching device in the rear-stage conversion circuit according to the output signal of the third comparator.

10. A power supply with a wide output voltage range as claimed in claim 9, characterized in that: The front-stage conversion circuit is an isolated conversion circuit, and the rear-stage conversion circuit is a non-isolated boost conversion circuit.

11. A power supply control method with a wide output voltage range, characterized in that: The method comprises providing a front-stage conversion circuit and a rear-stage conversion circuit, wherein the front-stage conversion circuit outputs a first voltage, and the rear-stage conversion circuit adjusts the first voltage to be converted into a second voltage. Accepting a second voltage reference value, when the second voltage reference value is less than a first set value, controlling the front-stage conversion circuit to output the minimum value of the first voltage, and then controlling the rear-stage conversion circuit to adjust the second voltage to follow the change of the second voltage reference value; when the second voltage reference value is not less than the first set value, controlling the front-stage conversion circuit to adjust the first voltage to follow the change of the second voltage reference value, and controlling the rear-stage conversion circuit to be in a direct-through state or a state of its maximum working duty cycle.

12. A power supply control method with a wide output voltage range, characterized in that: include, A front-stage conversion circuit and a rear-stage conversion circuit are provided, wherein the front-stage conversion circuit outputs a first voltage, and the rear-stage conversion circuit adjusts the first voltage to convert it into a second voltage. Accepting a second voltage reference value, when the second voltage reference value is greater than a second set value, controlling the front-stage conversion circuit to output the maximum value of the first voltage, and then controlling the rear-stage conversion circuit to adjust the second voltage to follow the change of the second voltage reference value; when the second voltage reference value is not greater than the second set value, controlling the front-stage conversion circuit to adjust the first voltage to follow the change of the second voltage reference value, and controlling the rear-stage conversion circuit to be in a direct-through state or a state of its maximum working duty cycle.

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