Power supply and power supply automatic switching method

Abstract

This invention discloses a power supply, including a transformer, a plurality of rectifier and filter circuits, and a multi-stage voltage regulator circuit. The transformer includes a primary winding and an auxiliary winding spaced apart on the primary side, and a secondary winding on the secondary side. The plurality of auxiliary coils in the auxiliary winding generate a plurality of auxiliary coil voltages based on the output voltage. The plurality of rectifier and filter circuits rectify and filter these auxiliary coil voltages to generate a plurality of rectified and filtered voltages. The plurality of linear voltage regulator circuits in the multi-stage voltage regulator circuit linearly regulate these rectified and filtered voltages to generate a plurality of linearly regulated voltages, and automatically switch between different power supply modes based on the output voltage, selecting the corresponding linear voltage regulator circuit among the plurality of linear voltage regulator circuits for power supply.

Claims

1. A power supply, comprising: A transformer for converting an input voltage into an output voltage includes: a primary winding disposed on the primary side of the transformer for receiving the input voltage; a secondary winding disposed on the secondary side of the transformer for outputting the output voltage; and an auxiliary winding disposed on the primary side of the transformer and spaced apart from the primary winding, the auxiliary winding including a plurality of auxiliary coils and the plurality of auxiliary coils generating a plurality of auxiliary coil voltages respectively according to the output voltage; A plurality of rectifier and filter circuits are coupled to the plurality of auxiliary coils respectively, for rectifying and filtering the voltages of the plurality of auxiliary coils to generate a plurality of rectified and filtered voltages; and a multi-stage voltage regulator circuit includes a plurality of linear voltage regulator circuits, each coupled to the plurality of rectifier and filter circuits, for linearly regulating the plurality of rectified and filtered voltages to generate a plurality of linearly regulated voltages, and automatically switching to different power supply modes according to the output voltage level to select the corresponding linear voltage regulator circuit among the plurality of linear voltage regulator circuits for power supply.

2. The power supply as claimed in claim 1, wherein the plurality of auxiliary coils are positively wound coils connected in series with each other.

3. The power supply as claimed in claim 1, wherein the plurality of auxiliary coils are reverse-wound coils connected in series with each other.

4. The power supply as claimed in claim 1, wherein the plurality of auxiliary coils are positively wound coils connected in parallel with each other.

5. The power supply as claimed in claim 1, wherein the plurality of auxiliary coils are reverse-wound coils connected in parallel with each other.

6. The power supply of claim 1, wherein each of the plurality of rectifier and filter circuits includes a rectifier element and a capacitor element, and each of the plurality of auxiliary coils independently uses the rectifier element of the corresponding rectifier and filter circuit.

7. The power supply of claim 1, wherein each of the plurality of rectifier-filter circuits includes a capacitor element, and the plurality of auxiliary coils share the same rectifier element located outside the rectifier-filter circuit.

8. The power supply as claimed in claim 1, wherein each of the plurality of linear voltage regulator circuits comprises: A bipolar junction transistor has a collector, an emitter, and a base. A resistive element, the two ends of which are respectively coupled to the collector and the base; The Zener diode is coupled between the base and the ground terminal; And a diode, coupled to the emitter.

9. The power supply as claimed in claim 1, wherein the first, second, and third rectifier filter circuits of the plurality of rectifier filter circuits are respectively coupled to the first, second, and third auxiliary coils of the plurality of auxiliary coils, and the first, second, and third linear regulator circuits of the multi-stage voltage regulator circuit are respectively coupled to the first, second, and third rectifier filter circuits; when the number of third coils of the third auxiliary coil > the number of second coils of the second auxiliary coil > the number of first coils of the first auxiliary coil, the third rectified and filtered voltage output by the third rectifier filter circuit is the same as the second rectified and filtered voltage output by the second rectifier filter circuit. The first rectified and filtered voltage, the first linearly regulated voltage output by the first linear regulator circuit, the second linearly regulated voltage output by the second linear regulator circuit, and the third linearly regulated voltage output by the third linear regulator circuit represent the power supply sequence of the multi-stage voltage regulator circuit as follows: the first linear regulator circuit, the second linear regulator circuit, and the third linear regulator circuit. When the output voltage is high, the multi-stage voltage regulator circuit switches to high-voltage power supply mode and is powered by the first linear regulator circuit. When the output voltage is medium, the multi-stage voltage regulator circuit switches to medium-voltage power supply mode and is powered by the second linear regulator circuit. When the output voltage is low, the multi-stage voltage regulator circuit switches to low-voltage power supply mode and is powered by the third linear regulator circuit.

10. The power supply as claimed in claim 1, wherein the number of sets of the plurality of auxiliary coils is a design constant, the highest value of the output voltage is the lowest value of the output voltage, the design constant is set to 1 or adjusted according to the winding area of ​​the transformer; the ratio of the number of turns of the plurality of auxiliary coils to the number of turns of the secondary winding is the power supply voltage output by the multi-stage voltage regulator circuit, and the preset output operating voltage of the plurality of auxiliary coils is the power supply voltage output by the multi-stage voltage regulator circuit.

11. An automatic power supply switching method applied to a power supply unit, the power supply unit including a transformer for converting an input voltage into an output voltage, the primary side of the transformer having a primary winding and an auxiliary winding spaced apart from each other, and the secondary side of the transformer having a secondary winding, the primary winding receiving the input voltage and the secondary winding outputting the output voltage, the auxiliary winding including a plurality of auxiliary coils, the automatic power supply switching method including the following steps: the plurality of auxiliary coils of the auxiliary winding generating a plurality of auxiliary coil voltages according to the output voltage; rectifying and filtering the plurality of auxiliary coil voltages to generate a plurality of rectified and filtered voltages; linearly regulating the plurality of rectified and filtered voltages to generate a plurality of linearly regulated voltages; and automatically switching different power supply modes according to the output voltage level and selecting the corresponding linearly regulated voltage from the plurality of linearly regulated voltages for output.

12. The automatic power supply switching method of claim 11, wherein the plurality of auxiliary coils includes at least a first auxiliary coil, a second auxiliary coil, and a third auxiliary coil; the plurality of rectified and filtered voltages includes at least a first rectified and filtered voltage, a second rectified and filtered voltage, and a third rectified and filtered voltage; the plurality of linearly regulated voltages includes at least a first linearly regulated voltage, a second linearly regulated voltage, and a third linearly regulated voltage; when the number of the third coil of the third auxiliary coil is equal to the number of the second coil of the second auxiliary coil is equal to the number of the first coil of the first auxiliary coil, the third rectified and filtered voltage, the second rectified and filtered voltage, and the first linearly regulated voltage, the second linearly regulated voltage, and the third linearly regulated voltage represent the power supply sequence of the plurality of linearly regulated voltages as the first linearly regulated voltage, the second linearly regulated voltage, and the third linearly regulated voltage; the automatic power supply switching method further includes the following step: determining whether the output voltage is high voltage, medium voltage, or low voltage; When the output voltage is determined to be high voltage, the system switches to high voltage power supply mode and selects to output the first linearly regulated voltage; when the output voltage is determined to be medium voltage, the system switches to medium voltage power supply mode and selects to output the second linearly regulated voltage; and when the output voltage is determined to be low voltage, the system switches to low voltage power supply mode and selects to output the third linearly regulated voltage.

13. The power supply automatic switching method as described in request item 11, wherein the number of the plurality of auxiliary coils is a design constant, the highest value of the output voltage is a minimum value of the output voltage, and the design constant is set to 1 or adjusted according to the winding area of ​​the transformer; the ratio of the number of turns of the plurality of auxiliary coils to the number of turns of the secondary winding outputs the linearly regulated voltage and the preset output operating voltage of the plurality of auxiliary coils.

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