Title:
DC POWER SUPPLY CIRCUIT
Document Type and Number:
WIPO Patent Application WO/2020/026601
Kind Code:
A1
Abstract:
A DC power supply circuit 1, provided with: a voltage adjustment circuit 2; a transformer 3 having a primary-side winding 3a connected to the voltage adjustment circuit 2; a transistor 4 connected to the primary-side winding 3a, the transistor 4 alternating between switching a current flowing through the primary-side winding 3a ON and OFF; a rectification circuit 5 connected to the secondary-side winding 3b of the transformer 3, the rectification circuit 5 converting the voltage outputted from the secondary-side winding 3b into a DC voltage; and a PWM control circuit 6 for controlling the ON/OFF duty ratio of the transistor 4 in accordance with a target voltage. If the target voltage is included in a first voltage range, the PWM control circuit 6 sets the duty ratio so as to be constant, and a transistor of the voltage adjustment circuit 2 operates in a linear region. If the target voltage is included in a second voltage range greater than the first voltage range, the PWM control circuit 6 varies the duty ratio in accordance with the target voltage, and the transistor of the voltage adjustment circuit 2 operates in a saturation region. It is thereby possible to enhance the stability of the output voltage while minimizing an increase in the size of a power supply device and an increase in power loss.
Inventors:
HIRAKAWA TOMOHIRO (JP)
Application Number:
PCT/JP2019/023364
Publication Date:
February 06, 2020
Filing Date:
June 12, 2019
Export Citation:
Assignee:
HAMAMATSU PHOTONICS KK (JP)
International Classes:
H02M3/28
Foreign References:
| JP2008148471A | 2008-06-26 | |||
| JPH0564439A | 1993-03-12 | |||
| JPH0622550A | 1994-01-28 |
Attorney, Agent or Firm:
HASEGAWA Yoshiki et al. (JP)
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