Protection circuit, drive system, chip and circuit protection method, and drive method

Abstract

The present disclosure provides a protection circuit, a drive system, a chip and a circuit protection method, and a drive method. The protection circuit can be used in a circuit system in which a load is driven by a switch circuit, and acquire a voltage signal reflecting the voltage of a power supply bus on which the load located and generate a detection signal, and control the switch circuit to maintain a forcible non-conductive state within a protection period when detecting that the voltage of the detection signal satisfies a preset voltage warning condition. The present application solves the problem of circuit protection of DC-powered electronics in the prior art.

What is claimed is: 
     
         1 . A protection circuit used in a linear LED driving system with high power factor that controls at least one switch circuit without any inductive element disposed therein, the protection circuit comprising:
 a detection unit configured to sense an undesirable oscillation of an output from a rectifying circuit to generate a detection result when the output of the rectifying circuit exceeds a preset threshold; and   a control unit coupled to the detection unit and configured to generate a control signal based on the detection result;   wherein the switch circuit being responsive to the control signal to be turned off for a protection period until the undesirable oscillation is disappeared.   
     
     
         2 . The protection circuit of  claim 1 , wherein the detection unit is coupled with the output of the rectifying circuit and configured to acquire an instantaneous voltage signal of the output of the rectifying circuit to generate the detection result. 
     
     
         3 . The protection circuit of  claim 1 , wherein the detection unit is coupled with the switch circuit and configured to sense a change the output of the rectifying circuit to generate the detection result. 
     
     
         4 . The protection circuit of  claim 1 , wherein the detection unit comprises:
 a sensing module, which senses the output of the rectifying circuit and outputs a detection signal; and   a detection module, configured to detect the detection signal and output the detection result when satisfying a preset voltage warning condition.   
     
     
         5 . The protection circuit of  claim 4 , wherein the sensing module comprises at least one capacitor coupled with the switch circuit to sense a voltage of the output of the rectifying circuit. 
     
     
         6 . The protection circuit of  claim 5 , wherein the capacitor is a parasite capacitor. 
     
     
         7 . The protection circuit of  claim 5 , wherein the sensing module further comprises at least one resistor connected in series with the capacitor to form a voltage divider that outputs the detection signal. 
     
     
         8 . The protection circuit of  claim 7 , wherein the switch circuit comprises at least one first switch power tube, wherein the capacitor is coupled with the first switch power tube to sense the voltage of the output of the rectifying circuit. 
     
     
         9 . The protection circuit of  claim 8 , wherein the capacitor is a parasite capacitor of a MOSFET, wherein a first terminal of the MOSFET is coupled with a control terminal of the first switch power tube, a second terminal of the MOSFET is coupled with the resistor. 
     
     
         10 . The protection circuit of  claim 8 , wherein a first terminal of the capacitor is coupled with one terminal of the first switch power tube, a second terminal of the capacitor is coupled with the resistor. 
     
     
         11 . The protection circuit of  claim 4 , wherein the sensing module is a voltage divider including a plurality of resistors, which is directly connected with the output of rectifying circuit. 
     
     
         12 . The protection circuit of  claim 4 , wherein the detection module comprises a comparator having a first input terminal for receiving the detection signal, a second input terminal for receiving a warning voltage threshold, wherein the comparator is configured to compare a voltage of the detection signal with the warning voltage threshold and output the detection result. 
     
     
         13 . The protection circuit of  claim 1 , wherein the control unit comprises a delay control module, connected with the detection unit, and configured to output a first control signal when the detection result indicates that a preset voltage warning condition is satisfied, and output a second control signal after a delay timing exceeds the protection period. 
     
     
         14 . The protection circuit of  claim 13 , wherein the control unit comprises a switch circuit control module, connected with an output terminal of the delay control module and a control terminal of the switch circuit, and configured to control the switch circuit to be turned off based on the first control signal, and turned on based on the second control signal. 
     
     
         15 . The protection circuit of  claim 14 , wherein the switch circuit control module comprises a voltage regulator, connected with the control terminal of the switch circuit, and configured to regulate a voltage on the control terminal of the switch circuit based on the first control signal and the second control signal. 
     
     
         16 . The protection circuit of  claim 14 , wherein the switch circuit control module comprises a driver, connected with an input terminal of the switch circuit, and configured to control a drive unit of the switch circuit based on the first control signal and the second control signal. 
     
     
         17 . The protection circuit of  claim 1 , wherein the undesirable oscillation of the output comes from a ringing wave superimposed on an AC input power. 
     
     
         18 . A linear LED circuit system with high power factor, comprising:
 a rectifying circuit, connected with an AC voltage with no protection element interposed therebetween;   a protection circuit, coupled with an output of the rectifying circuit, comprising:
 a detection unit configured to sense an undesirable oscillation of an output from the rectifying circuit to generate a detection result when the output exceeds a preset threshold; and 
 a control unit coupled to the detection unit and configured to generate a control signal based on the detection result; and 
   at least one switch circuit without any inductive element disposed therein, connected in series with a string of LEDs, the switch circuit being responsive to the control signal to be turned off for a protection period to until the undesirable oscillation is disappeared.   
     
     
         19 . The linear LED circuit system of  claim 18 , wherein the switch circuit comprises a drive unit and a first switch power tube, the detection unit comprises a sensing module to sense a voltage of the output of the rectifying circuit to output a detection signal, wherein the sensing module is coupled with the first switch power or directly connected with the output of the rectifying circuit. 
     
     
         20 . The linear LED circuit system of  claim 19 , wherein the sensing module is a voltage divider that senses the voltage of the output of the rectifying circuit to output the detection signal. 
     
     
         21 . The linear LED circuit system of  claim 20 , wherein the voltage divider comprises at least two resistors connected in series or at least one capacitor and a resistor connected in series to sense the voltage of the output of the rectifying circuit. 
     
     
         22 . The linear LED circuit system of  claim 21 , wherein the capacitor is a parasite capacitor of a MOSFET switch, wherein a first terminal of the MOSFET switch is coupled with the control terminal of the first switch power tube, a second terminal of the MOSFET switch is connected with the resistor, a control terminal of the MOSFET switch is controlled by a voltage supplier. 
     
     
         23 . The protection circuit of  claim 19 , wherein the detection unit comprises a comparator configured to compares the detection signal with a warning voltage threshold to decide whether to output the detection result. 
     
     
         24 . The linear LED circuit system of  claim 18 , wherein the undesirable oscillation of the output comes from a ringing wave superimposed on an AC input power.