JPH01105379U

JPH01105379U -

Info

Publication number: JPH01105379U
Application number: JP20120287U
Authority: JP
Priority date: 1987-12-29
Filing date: 1987-12-29
Publication date: 1989-07-17

Description

[Brief explanation of the drawing]

第１図および第２図はそれぞれ本考案の実施例
を示す回路構成図、第３図は従来例を示す回路構
成図、第４図は出力短絡時のドレイン電流波形で
ある。１……パワーＭＯＳＦＥＴ、２……電流検出抵
抗、３……電流検出端子、４……コンパレータ、
５……基準電圧、６……ＳＲフリツプフロツプ、
７……セツト信号発生器、８……ＰＷＭコンパレ
ータ、９……発振器、１０……ＡＮＤ回路、１１
……分周器、１２……コレクタ端子、１３，１４
……出力トランジスタ、１５……出力端子、１６
……基準電圧、１７……定電流源、１８……トラ
ンジスタ、１９……放電用抵抗、２０……出力パ
ルスオンデユーテイ検出端子、２１……出力パル
スオンデユーテイ検出用コンデンサ、２２……ト
ランジスタ、２３……出力パルスオンデユーテイ
検出用抵抗、２４……出力パルスオンデユーテイ
検出用コンデンサ、２５，２６……Ｓｗ・Ｒｅｇ
ＩＣ（一点鎖線内）。 1 and 2 are circuit configuration diagrams showing an embodiment of the present invention, FIG. 3 is a circuit configuration diagram showing a conventional example, and FIG. 4 is a drain current waveform when an output is short-circuited. 1...Power MOSFET, 2...Current detection resistor, 3...Current detection terminal, 4...Comparator,
5...Reference voltage, 6...SR flip-flop,
7... Set signal generator, 8... PWM comparator, 9... Oscillator, 10... AND circuit, 11
...Frequency divider, 12...Collector terminal, 13, 14
... Output transistor, 15 ... Output terminal, 16
... Reference voltage, 17 ... Constant current source, 18 ... Transistor, 19 ... Discharge resistor, 20 ... Output pulse on duty detection terminal, 21 ... Output pulse on duty detection capacitor, 22 ... Transistor, 23... Resistor for output pulse on duty detection, 24... Capacitor for output pulse on duty detection, 25, 26... Sw・Reg
IC (within the dashed line).

Claims

[Scope of utility model registration request]

A switching regulator control IC equipped with a latch type overcurrent protection function includes a transistor that is turned on and off by the output of a frequency divider that drives the output transistor, and a constant current source that flows a constant current when the transistor is turned on. A terminal for charging an external capacitor with a constant current, and a G terminal between the terminal and the switching regulator control IC.
A switching regulator control IC equipped with a latch type overcurrent protection function, comprising a discharge resistor connected between ND and a function to detect on-duty of an output pulse.