Leakage protection circuit, method and drive device

Abstract

The present disclosure provides a leakage protection circuit, a method and a drive device. The leakage protection circuit is used for being electrically connected with the power supply line of a load, and may be configured to sample the power supply line at intervals, detect the voltage of the sampled electrical signals to determine whether the voltage of the AC input power is divided, and provide leakage protection based on the determined result. The present disclosure can prevent human from electric shock through sampling the electric signals from the power supply line at intervals and performing voltage detection and comparasion to determine whether the voltage of the accessed AC input power is divided, when the voltage of the accessed AC input power is determined to be divided, the power supply line will be controlled in non-conductive state.

1 . A leakage protection circuit, used for being electrically connected with a power supply line of a load, the leakage protection circuit being configured to sample a power supply line voltage at intervals, detect the sampled power supply line voltage to determine whether a voltage of an AC input power is divided, and provide leakage protection based on the determined result. 
     
     
         2 . The leakage protection circuit of  claim 1 , comprising:
 a detection unit, connected with the power supply line, and configured to output a sampling control signal based on the detection of the power supply line voltage;   a sampling unit, connected with the detection unit, and configured to sample an electrical signal from the power supply line based on the received sampling control signal; and   a control unit, connected with the sampling unit, and configured to compare the voltage of the sampled electrical signal with a predetermined power-off protection voltage threshold and provide leakage protection based on the compared result.   
     
     
         3 . The leakage protection circuit of  claim 2 , wherein the detection unit comprises a limited voltage detection circuit module which is connected with the power supply line and configured to detect the power supply line voltage and output a first sampling control signal when the detected power supply line voltage falls within predetermined limited voltage range. 
     
     
         4 . The leakage protection circuit of  claim 3 , wherein the detection unit further comprises a timing circuit module which is connected with the limited voltage detection circuit module and configured to output a second sampling control signal based on the first sampling control signal. 
     
     
         5 . The leakage protection circuit of  claim 4 , wherein the timing circuit module is configured to set a detection timing based on the first sampling control signal, and output the second sampling control signal after the detection timing is exceeded. 
     
     
         6 . The leakage protection circuit of  claim 4 , wherein the timing circuit module is configured to output the second sampling control signal within an existence duration of the first sampling control signal. 
     
     
         7 . The leakage protection circuit of  claim 1 , wherein the interval is set based on a change period of the power supply line voltage or based on a predetermined duration. 
     
     
         8 . The leakage protection circuit of  claim 2 , wherein the control unit comprises:
 a comparison circuit module, configured to compare the voltage of the sampled electrical signal with the predetermined power-off protection voltage threshold and output the compared result; and   a logic latch circuit module, connected with the comparison circuit module, and configured to latch the compared result and output a corresponding latch signal, wherein the latch signal is representing a leakage protection control signal generated by the leakage protection circuit.   
     
     
         9 . The leakage protection circuit of  claim 8 , wherein the control unit further comprises: a switch circuit module which is connected with the logic latch circuit module and configured to control a conductive state or a non-conductive state of the power supply line. 
     
     
         10 . The leakage protection circuit of  claim 1 , wherein the leakage protection circuit is configured to stop sampling the power supply line voltage at intervals when the power supply line is controlled to be conductive. 
     
     
         11 . The leakage protection circuit of  claim 1 , wherein the leakage protection circuit is an LED leakage protection circuit used for being electrically connected with the power supply line of an LED load, and the LED leakage protection circuit is configured to output a leakage protection control signal based on the determined result, in order that an LED drive circuit electrically connected with the LED leakage protection circuit gives a corresponding leakage protection response based on the leakage protection control signal. 
     
     
         12 . A chip, comprising:
 multiple pins, wherein at least one pin of the multiple pins is electrically connected with a power supply line of a load;   a leakage protection circuit, connected with the pin and configured to sample a power supply line voltage at intervals, detect the sampled power supply line voltage to determine whether a voltage of an AC input power is divided, and provide leakage protection based on the determined result.   
     
     
         13 . The chip of  claim 12 , wherein the leakage protection circuit comprises:
 a detection unit, connected with the power supply line, and configured to output a sampling control signal based on the detection of the power supply line voltage;   a sampling unit, connected with the detection unit, and configured to sample an electrical signal from the power supply line based on the received sampling control signal; and   a control unit, connected with the sampling unit, and configured to compare the voltage of the sampled electrical signal with a predetermined power-off protection voltage threshold and provide leakage protection based on the compared result.   
     
     
         14 . The chip of  claim 13 , wherein the detection unit comprises a limited voltage detection circuit module which is connected with the power supply line and configured to detect the power supply line voltage and output a first sampling control signal when the detected power supply line voltage falls within a predetermined limited voltage range. 
     
     
         15 . The chip of  claim 14 , wherein the detection unit further comprises a timing circuit module which is connected with the limited voltage detection circuit module and configured to output a second sampling control signal based on the first sampling control signal. 
     
     
         16 . The chip of  claim 12 , wherein the interval is set based on a change period of the power supply line voltage or based on a predetermined duration. 
     
     
         17 . The chip of  claim 13 , wherein the control unit comprises:
 a comparison circuit module, configured to compare the voltage of the sampled electrical signal with the predetermined power-off protection voltage threshold and output the compared result; and   a logic latch circuit module, connected with the comparison circuit module, and configured to latch the compared result and output a corresponding latch signal, wherein the latch signal is representing a leakage protection control signal generated by the leakage protection circuit.   
     
     
         18 . The chip of  claim 17 , wherein the control unit further comprises: a switch circuit module which is connected with the logic latch circuit module and configured to control a conductive state or a non-conductive state of the power supply line. 
     
     
         19 . The chip of  claim 12 , wherein the leakage protection circuit is an LED leakage protection circuit, and is electrically connected with a power supply line of an LED load via the pin. 
     
     
         20 . A drive device, comprising:
 a rectifying circuit, configured to rectify the accessed AC and then provide to a power supply line of a load;   a leakage protection circuit, connected with the rectifying circuit and configured to sample a power supply line voltage at intervals, detect the sampled power supply line voltage to determine whether a voltage of an AC input power is divided, and provide leakage protection based on the determined result; and   a drive circuit, connected with the leakage protection circuit and configured to supply power to the load based on the current rectified by the rectifying circuit.   
     
     
         21 . The drive device of  claim 20 , wherein the leakage protection circuit comprises:
 a detection unit, connected with the power supply line, and configured to output a sampling control signal based on the detection of the power supply line voltage;   a sampling unit, connected with the detection unit, and configured to sample an electrical signal from the power supply line based on the received sampling control signal; and   a control unit, connected with the sampling unit, and configured to compare the voltage of the sampled electrical signal with a predetermined power-off protection voltage threshold and provide leakage protection based on the compared result.   
     
     
         22 . The drive device of  claim 21 , wherein the detection unit comprises a limited voltage detection circuit module which is connected with the power supply line and configured to detect the power supply line voltage and output a first sampling control signal when the detected voltage falls within a predetermined limited voltage range. 
     
     
         23 . The drive device of  claim 22 , wherein the detection unit further comprises a timing circuit module which is connected with the limited voltage detection circuit module and configured to output a second sampling control signal based on the first sampling control signal. 
     
     
         24 . The drive device of  claim 21 , wherein the control unit comprises:
 a comparison circuit module, configured to compare the voltage of the sampled electrical signal with the predetermined power-off protection voltage threshold and output the compared result; and   a logic latch circuit module, connected with the comparison circuit module, and configured to latch the compared result and output a corresponding latch signal, wherein the latch signal is representing the leakage protection control signal generated by the leakage protection circuit.   
     
     
         25 . The drive device of  claim 24 , wherein the leakage protection circuit is configured to output the leakage protection control signal to the drive circuit; and
 the drive circuit gives a corresponding leakage protection response based on the leakage protection control signal.   
     
     
         26 . The drive device of  claim 25 , wherein the drive circuit comprises an enable control unit, and the enable control unit is configured to give a corresponding leakage protection response based on the leakage protection control signal when the leakage protection circuit outputs the leakage protection control signal. 
     
     
         27 . A leakage protection method, comprising:
 sampling a power supply line voltage of a load at intervals;   detecting the sampled power supply line voltage to determine whether a voltage of an AC input power to which the power supply line is accessed is divided; and   providing leakage protection based on the determined result.   
     
     
         28 . The leakage protection method of  claim 27 , wherein the manner of sampling the power supply line voltage of a load at intervals comprises:
 performing a limited voltage detection on the power supply line voltage; and   acquiring a sampled electrical signal from the power supply line based on a result of the limited voltage detection.   
     
     
         29 . The leakage protection method of  claim 28 , wherein the manner of acquiring the sampled electrical signal from the power supply line based on a result of the limited voltage detection comprises: acquiring a sampled electrical signal from the power supply line after a predetermined detection timing is exceeded and the power supply line voltage falls within a predetermined limited voltage range. 
     
     
         30 . The leakage protection method of  claim 27 , wherein the interval is set based on a change period of the power supply line voltage or based on a predetermined duration. 
     
     
         31 . The leakage protection method of  claim 27 , wherein the manner of detecting the sampled power supply line voltage to determine whether the voltage of the AC input power to which the power supply line is accessed is divided comprises: comparing the sampled power supply line voltage with a predetermined power-off protection voltage threshold, and determining whether the voltage of the AC input power is divided based on the compared result. 
     
     
         32 . The leakage protection method of  claim 27 , wherein the manner of providing leakage protection based on the determined result comprises:
 controlling the power supply line to be conductive when the determined result is that the voltage of the AC input power is not divided; and controlling the power supply line to be non-conductive when the determined result is that the voltage of the AC input power is divided; or   controlling a drive circuit to supply power to the load when the determined result is that the voltage of the AC input power is not divided; and controlling the drive circuit to give a leakage protection response when the determined result is that the voltage of the AC input power is divided.