SWITCHING POWER SUPPLY CIRCUIT

• Main Author: HATA TAKEHIRO
• Format: Patent
• Language: English; Japanese
• Published: 23.06.2016
• 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 switching power supply circuit, capable of realizing fast response at load fluctuation, without degrading efficiency at normal operation.SOLUTION: An output circuit 1 includes MOSFET2 and 3 connected between a power supply terminal VD and a ground terminal for charging a capacitor 5 through an inductor 4. An output voltage Vout is detected as a monitor voltage Vfb, and generates an error signal Verr by an error amplifier 7. A comparator 11 of a driver circuit 10, to which the error signal Verr and a triangular wave signal from an oscillator circuit 12 are given, generates a PWM signal and drives the MOSFET2 and 3. The oscillator circuit 12 outputs a triangular wave signal at a first frequency f1 in normal operation, and the frequency is switched to a second frequency f2, higher than the first frequency, by being given a detection signal S from a detection circuit 15 if load fluctuation exceeds a predetermined range. Thus, voltage fluctuation is suppressed with the higher frequency, and back to normal operation if the fluctuation subsides.SELECTED DRAWING: Figure 1 【課題】通常動作時の効率を下げることなく、負荷変動時においても高速応答を実現できるようにしたスイッチング電源回路を提供する。【解決手段】出力回路１は、電源端子ＶＤとグランド端子との間にＭＯＳＦＥＴ２、３を接続し、コイル４からコンデンサ５に充電する。出力電圧Ｖｏｕｔはモニタ電圧Ｖｆｂとして検出され、誤差増幅器７で誤差信号Ｖｅｒｒを生成する。駆動回路１０のコンパレータ１１は、誤差信号Ｖｅｒｒと発振回路１２からの三角波信号が与えられ、ＰＷＭ信号を生成してＭＯＳＦＥＴ２、３を駆動する。発振回路１２は、通常時に第１周波数ｆ１の三角波信号を出力し、負荷変動が所定範囲を超えると検出回路１５から検出信号Ｓが与えられて高い周波数の第２周波数ｆ２に切り換えられる。これにより、負荷変動時には高い周波数で電圧変動を抑え、変動が収まると通常状態に戻ることができる。【選択図】図１