US 12,355,228 B2
Fault protection for security system controllers
Nilesh Ashok Naik, Sawantawadi Maharastra (IN); Ankit Panchal, Milwaukee, WI (US); and Ankit Sinha, Milwaukee, WI (US)
Assigned to TYCO FIRE & SECURITY GMBH, Neuhausen am Rheinfall (CH)
Filed by TYCO FIRE & SECURITY GMBH, Neuhausen am Rheinfall (CH)
Filed on Jul. 12, 2022, as Appl. No. 17/863,160.
Prior Publication US 2024/0022060 A1, Jan. 18, 2024
Int. Cl. H02H 3/08 (2006.01); H02H 1/00 (2006.01); H02H 9/02 (2006.01); G08B 13/00 (2006.01)
CPC H02H 3/08 (2013.01) [H02H 1/0007 (2013.01); G08B 13/00 (2013.01)] 16 Claims
OG exemplary drawing
 
1. A protection circuit, comprising:
a first transistor having a first source, a first gate, and a first drain; wherein the first drain is coupled to an input of the protection circuit through a shunt resistor and the first source is coupled to an output of the protection circuit, wherein the protection circuit is coupled to a power source at the input of the protection circuit;
a diode, wherein a cathode of the diode is coupled to the first source of the first transistor, wherein the diode is a Zener diode;
an overcurrent protection circuit, coupled to the first transistor, wherein the overcurrent protection circuit comprises:
a second transistor having a second source, a second gate, and a second drain, wherein the second transistor is coupled between the first source and an output of the protection circuit, and
a voltage divider coupled to the input of the protection circuit, wherein an intermediate point of the voltage divider is coupled to the second gate;
a third transistor coupled in parallel with a first resistor of the voltage divider; and
a second resistor, coupled between an anode of the diode and ground such that one electrode of the second resistor is coupled directly to ground and another electrode of the second resistor is coupled to the anode of the diode, wherein a first polarity of the input opens a channel of the first transistor, and a second polarity of the input closes the channel of the first transistor.