Power circuit

Abstract

This invention provides a power supply circuit that generates an output voltage that is at least two integer multiples smaller than the input voltage, using an inexpensive configuration that involves adding only a few components to a low-cost multi-stage chopper. [Solution] A power supply circuit comprising a low-cost multi-stage chopper (where the anode of D1 of the first step-down chopper circuit is connected to a common line, the cathode of D1 is connected to one terminal of L1, the other terminal of L1 is connected to one terminal of C1, and the other terminal of C1 is connected to a common line; where one terminal of C2 of the second step-down chopper circuit is connected to the cathode of D1, the other terminal of C2 is connected to the cathode of D2, the anode of D2 is connected to the other terminal of L1, one terminal of L2 is connected to the cathode of D2, the other terminal of L2 is connected to one terminal of C3, and the other terminal of C3 is connected to a common line, and a first output voltage is generated in C1 and a larger second output voltage in C3 by control of Q1), and output voltage changing means for changing the first and / or second output voltages.

Claims

1. A power supply circuit that generates at least two output voltages smaller than the input voltage with respect to the input voltage, A first step-down chopper circuit that generates a first output voltage with respect to a common line, It includes a second step-down chopper circuit that generates a second output voltage with reference to the aforementioned common line, The first step-down chopper circuit comprises a first diode, a first coil, and a first capacitor. The anode of the first diode is connected to the common line via the first power line, The cathode of the first diode is connected to one terminal of the first coil via a second power line. The other terminal of the first coil is connected to one terminal of the first capacitor via a third power line. The other terminal of the first capacitor is connected to the common line via the fourth power line, The second step-down chopper circuit comprises second and third capacitors, a second diode, and a second coil. One terminal of the second capacitor is connected to the cathode of the first diode via a fifth power line connected to the second power line. The other terminal of the second capacitor is connected to the cathode of the second diode via a sixth power line. The anode of the second diode is connected to the other terminal of the first coil via a seventh power line connected to the third power line. One terminal of the second coil is connected to the cathode of the second diode via an eighth power line connected to the sixth power line. The other terminal of the second coil is connected to one terminal of the third capacitor via the ninth power line. The other terminal of the third capacitor is connected to the common line via the tenth power line, By controlling the switching element, a first output voltage is generated across the first capacitor, and a second output voltage greater than the first output voltage is generated across the third capacitor. Furthermore, the power supply circuit is characterized in that the first step-down chopper circuit and / or the second step-down chopper circuit are provided with output voltage changing means for changing the first output voltage and / or the second output voltage.

2. The power supply circuit according to claim 1, characterized in that the output voltage changing means is a third diode.

3. The third diode is a Zener diode, The first power line is interposed in the opposite direction to the orientation of the first diode, or Interposed in the seventh power line in the opposite direction to the second diode, The power supply circuit according to feature 2.

4. The third diode is a diode other than a Zener diode. The first power line is interposed in the same orientation as the first diode, or Interposed in the seventh power line in the same orientation as the second diode, The power supply circuit according to feature 2.

5. The power supply circuit according to any one of claims 2 to 4, characterized in that the third diode is a plurality of diodes arranged in series.

6. The power supply circuit according to any one of claims 2 to 4, characterized in that the third diode has a different resistance value from the first diode and the second diode.

7. The power supply circuit according to claim 1, characterized in that the output voltage changing means is a resistor.

8. The aforementioned resistor is Interposed in the first power line or the seventh power line, The power supply circuit according to feature 7.

9. The power supply circuit according to claim 1, characterized in that the output voltage changing means is an output voltage changing switching element.

10. The power supply circuit according to claim 9, characterized in that the output voltage changing switching element is interposed in the fifth power line.

11. The power supply circuit according to claim 9 or 10, characterized in that the ON width of the output voltage changing switching element is smaller than the ON width of the switching element.

12. The on-width and off-width of the output voltage changing switching element are the same as the on-width and off-width of the switching element. The power supply circuit according to claim 9 or 10, characterized in that the timing at which the output voltage changing switching element switches between on and off is different from the timing at which the switching element switches between on and off.

13. The power supply circuit according to claim 1, characterized in that the output voltage changing means is a third coil.

14. The third coil is, The first power line, or The second power line, or The fifth power line, or The sixth power line, or Interposed in the aforementioned seventh power line, The power supply circuit according to feature 13.

15. The power supply circuit according to claim 1, characterized in that the output voltage changing means includes a fourth coil and a frequency changing means for changing the frequency of the switching element.

16. The fourth coil is, The sixth power line, or It is interposed in the seventh power line, The power supply circuit according to claim 15, characterized in that the frequency changing means changes the frequency by changing the off-width of the switching element.

Images