A LED driving power supply and its output terminal short-circuit protection circuit
A short-circuit protection circuit and LED driving technology, which is applied in the direction of over-current protection, can solve the problems of long short-circuit recovery time, large output voltage fluctuation, and large power consumption, and achieve short-circuit recovery time and overcome power consumption. high effect
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Embodiment 1
[0037] figure 1 A structural diagram of an output terminal short-circuit protection circuit of an LED driving power supply provided by an embodiment of the present invention. Such as figure 1 As shown, the short-circuit protection circuit at the output end of the LED drive power supply includes: a short-circuit detection circuit 1 and a short-circuit shutdown circuit 2, the short-circuit detection circuit 1 includes a comparator CP, a non-inverting input circuit 10 and an inverting input circuit 11, and the short-circuit The shutdown circuit 2 includes a switch tube;
[0038] Both the non-inverting input terminal circuit 10 and the inverting input terminal circuit 11 are connected to the positive output terminal Uo of the LED drive power supply, and are respectively connected to the non-inverting input terminal and the inverting input terminal of the comparator CP. At the positive power supply terminal LED+ of the LED load 3 In the short-circuit state of the negative power s...
Embodiment 2
[0046] Such as figure 2 As shown, on the basis of the above embodiments, the inverting input circuit 11 specifically includes a first resistor R1 and a second resistor R2, and the non-inverting input circuit 10 specifically includes a third resistor R3, a fourth resistor R4, a PNP transistor Q2, The sixth resistor R6 and the seventh resistor R7;
[0047] Wherein, the first resistor R1 and the second resistor R2 are connected in series, the common terminal A of the two is connected with the inverting input terminal of the comparator CP, the other terminal of the first resistor R1 is connected with the positive output terminal Uo of the LED driving power supply, and the second The other end of the resistor R2 is grounded.
[0048] The third resistor R3 and the fourth resistor R4 are connected in series, the common terminal B of the two is connected to the non-inverting input terminal of the comparator CP, the other end of the third resistor R3 is connected to the collector of ...
Embodiment 3
[0055] image 3 The circuit diagram of short-circuit protection at the output end of another LED driving power supply provided by the embodiment of the present invention. Such as image 3 As shown, the inverting input circuit 11 specifically includes a first resistor R1 and a second resistor R2, and the non-inverting input circuit 10 specifically includes a third resistor R3, a fourth resistor R4, a PNP transistor Q2, a sixth resistor R6, and a seventh resistor R7, Zener diode Z and capacitor C;
[0056] Wherein, the first resistor R1 and the second resistor R2 are connected in series, the common terminal A of the two is connected with the inverting input terminal of the comparator CP, the other terminal of the first resistor R1 is connected with the positive output terminal UO of the LED driving power supply, and the second The other end of the resistor R2 is grounded;
[0057] The third resistor R3 and the fourth resistor R4 are connected in series, the common terminal B ...
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