CURRENT MODE CONTROL TYPE SWITCHING POWER SUPPLY DEVICE

• Main Author: YAMAGUCHI YUHEI
• Format: Patent
• Language: English; Japanese
• Published: 19.07.2018
• Subjects: APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC,OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWERSUPPLY SYSTEMS; CONTROL OR REGULATION THEREOF; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUTPOWER; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER; ELECTRICITY; GENERATION

PROBLEM TO BE SOLVED: To provide a current mode control type switching power supply device capable of performing current feedback even when a ratio of output voltage to input voltage is small, the current feedback being independent of the input voltage and output current.SOLUTION: A switching power supply device 101 includes: a first switch Q1; a second switch Q2; a current sense circuit 4 for sensing current flowing through the second switch Q2; and a control unit. The control unit includes: a capacitor; a constant current source; a third switch for electrically connecting/disconnecting a current path from the current sense circuit 4 to the capacitor; and a fourth switch for electrically connecting/disconnecting a current path from the constant current source to the capacitor. The control unit controls the first switch Q1 and the second switch Q2 depending on a charge voltage of the capacitor. There is provided an off period in which both of the third switch and the fourth switch are off.SELECTED DRAWING: Figure 1 【課題】入力電圧に対する出力電圧の比が小さい場合でも電流帰還が可能であって、当該電流帰還が入力電圧及び出力電流に依存しない電流モード制御型スイッチング電源装置を提供する。【解決手段】スイッチング電源装置１０１は、第１スイッチＱ１と、第２スイッチＱ２と、第２スイッチＱ２を流れる電流を検出する電流検出回路４と、制御部と、を備える。前記制御部は、コンデンサと、定電流源と、電流検出回路４から前記コンデンサに至る電流経路を導通／遮断する第３スイッチと、前記定電流源から前記コンデンサに至る電流経路を導通／遮断する第４スイッチと、を有する。前記制御部は、前記コンデンサの充電電圧に応じて第１スイッチＱ１及び第２スイッチＱ２を制御する。前記第３スイッチ及び前記第４スイッチがともにオフであるオフ期間が設けられている。【選択図】図１