# US 9,520,791 B2 · Power controller with multi-function pin and power supply using the same > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,520,791 B2 - Document ID: US9520791B2 - Status: Granted - Kind: B2 - Application number: 13/798,148 - Filed: 2013-03-13 - Published: 2013-11-14 - Granted: 2016-12-13 - Earliest claimed: 2012-05-11 - Assignees: Leadtrend Technology Corp. - Applicants: Leadtrend Technology Corp. - Inventors: Chin-Ho Wu; Ren-Yi Chen; Yi-Shan Chu - Web page: https://patentgrep.com/patent/US9520791B2 ## CPC - H02M 3/325: using devices of a triode or a transistor type requiring continuous application of a control signal - H02M 1/0064: {Magnetic structures combining different functions, e.g. storage, filtering or transformation} - H02M 3/33507: {with automatic control of the output voltage or current, e.g. flyback converters (H02M3/33561, H02M3/33569 take precedence)} - H02M 1/327: {against abnormal temperatures} - H02M: APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF (transformers H01F; dynamo-electric converters H02K47/00; controlling transformers, reactors or choke coils, control or regulation of electric motors, generators or dynamo-electric converters H02P) ## Abstract Power supplies and power controllers are disclosed. A disclosed power supply has a power controller, a power switch, an auxiliary winding, a first circuit and a second circuit. The power controller is a monolithic integrated circuit with a multi-function pin and a gate pin. A control node of the power switch is coupled to the gate pin. The first circuit is coupled between the multi-function pin and the auxiliary winding and has a diode. The second circuit is coupled between the multi-function pin and a ground line, and has a thermistor. ## Claims ### Claim 1 A power supply, comprising: a power controller having a multi-function pin, an FB pin, a CS pin, and a gate pin, wherein the power controller is a monolithic integrated circuit; a power switch having a control terminal coupled to the gate pin, wherein the FB pin different to the CS pin and the multi-function pin is used for receiving a feedback signal corresponding to a voltage of an output terminal of the power supply; an auxiliary winding; a first circuit coupled between the multi-function pin and the auxiliary winding, wherein the first circuit has a diode; and a second circuit coupled between the multi-function pin and a ground line, wherein the second circuit has a thermistor coupled between the multi-function pin and the ground line, a resistance of the second circuit is varied with a resistance of the thermistor, and the resistance of the second circuit is used for determining whether an over temperature protection signal is enabled; wherein when a voltage signal of the CS pin exceeds a value corresponding to the feedback signal, the power switch is turned off, and when the power switch is turned off, the power controller detects a discharge time of the auxiliary winding through the multi-function pin. ### Claim 2 (depends on 1) The power supply of claim 1, wherein the first circuit comprises the diode and a resistor, where the diode and the resistor are coupled between the multi-function pin and the auxiliary winding in series. ### Claim 3 (depends on 1) The power supply of claim 1, wherein the second circuit has the thermistor and a resistor, where the thermistor and the resistor are coupled between the multi-function pin and the ground line in series. ### Claim 4 (depends on 1) The power supply of claim 1, wherein the power controller detects a discharge time of the auxiliary winding through the multi-function pin when the power switch is turned off. ### Claim 5 (depends on 1) The power supply of claim 1, wherein the power controller detects a resistance of the second circuit through the multi-function pin when the power switch is turned on. ### Claim 6 A power controller being a monolithic integrated circuit, the power controller comprising: a gate pin for outputting a gate signal; a CS pin for detecting a current flowing through a power switch controlled by the gate signal; an FB pin for receiving a feedback signal corresponding to a voltage of an output terminal of a power supply which the power controller is applied to, wherein when a voltage signal of the CS pin exceeds a value corresponding to the feedback signal, the power switch is turned off; a multi-function pin different to the FB pin and the CS pin coupled to a ground line through a thermistor; a resistance detector for detecting a resistance between the multi-function pin and the ground line when the gate signal is enabled, and enabling an over temperature protection signal when the resistance is lower than a predetermined value, wherein the resistance is varied with a resistance of the thermistor; and a quadrature resonance (QR) detector for detecting a discharge time of an external inductor through the multi-function pin to enable a trigger signal when the gate signal is disabled; wherein the trigger signal enables the gate signal, and the enabled protection signal keeps the gate signal not being enabled. ### Claim 7 (depends on 6) The power controller of claim 6, wherein the resistance detector outputs a fixed first current through the multi-function pin and detects a pin voltage of the multi-function pin when the gate signal is enabled, and the resistance detector enables the protection signal when the pin voltage is higher than a predetermined voltage. ### Claim 8 (depends on 6) The power controller of claim 6, wherein the QR detector detects an input current inputted from the multi-function pin when the gate signal is disabled, and the QR detector enables the trigger signal when the input current is smaller than predetermined current. ### Claim 9 (depends on 6) The power controller of claim 6, wherein the resistance detector comprises: a first current source for providing a first current outputted from the multi-function pin; and a voltage comparator for comparing a pin voltage of the multi-function pin with a predetermined voltage. ### Claim 10 (depends on 6) The power controller of claim 6, wherein the QR detector comprises: a current comparator for comparing an input current inputted from the multi-function pin with a predetermined current.