A kind of protection circuit and method
A technology for protecting circuits and circuits, applied in emergency protection circuit devices, circuit devices, emergency protection devices with automatic disconnection, etc., can solve problems such as damage to active switching devices of boost circuits, and achieve the effect of preventing damage.
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Embodiment 1
[0040] The protection circuit provided by this embodiment is applied to a boost circuit, and the boost circuit is provided with an input-to-output through circuit formed by the parasitic diode of the first switch, such as image 3 As shown, the circuit includes: an overcurrent detection circuit 31, a first control circuit 32, and a second switch 33; among them,
[0041] The overcurrent detection circuit 31 samples the first current flowing through the first switch; and detects whether the first current meets a first condition; when the first current meets the first condition, the The first control circuit 32 outputs a first control signal to the second switch 33; the second switch 33 turns off the through circuit in response to the first control signal.
[0042] Here, the first condition indicates that the output current of the boost circuit is overcurrent.
[0043] In the embodiment of the present invention, the boost circuit is provided with an input-to-output through circuit forme...
Embodiment 2
[0072] This example is Figure 5 A specific application example of the circuit shown.
[0073] In this embodiment, as Image 6 As shown, the boost circuit 61 includes: an inductor L, a MOS transistor Q1, a MOS transistor Q2, an input terminal capacitor Cin, and an output terminal capacitor Cout1;
[0074] The over-current detection circuit (OC) 31 samples the current flowing through the MOS transistor Q2 and judges whether it is over-current;
[0075] The first control circuit 32 includes a PMOS logic control circuit (PMOS Control);
[0076] The second switch 33 includes a PMOS transistor Q3;
[0077] The second control circuit 34 includes a resistor R1, a resistor R2, an error operational amplifier EA0, a comparator Comp1, a first SR latch SR1, a pulse width modulation (PWM) logic control circuit (PWM Control), and an inverter INV1. The resistor R1, the resistor R2, the error operational amplifier EA0, the comparator Comp1, and the first SR latch SR1 form a current loop negative feedb...
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