Patent ID: 11867571
Assignee: NXP B.V.
Field: Measurement (Instruments)
Classification: CPC G  H | IPC G  H

Claim 9:
10. A temperature detection method, comprising:
generating a reference voltage VREF with a reference voltage generator;
providing first and second bias currents to a current conveyor which is connected to a ground reference voltage over a startup circuit comprising:
a first FET device having a gate terminal connected to receive the reference voltage VREF, a drain terminal connected to the ground reference voltage, and a source terminal connected to provide a first input voltage VS1 to the current conveyor,
a first diode-connected bipolar junction transistor (BJT) device having base and collector terminals connected to the ground reference voltage and an emitter terminal connected to provide a base-emitter voltage, and
a second FET device having gate and drain terminals connected to receive the base-emitter voltage from the first diode-connected BJT device and a source terminal connected to provide a second input voltage VS2 to the current conveyor in response to variations in a device junction temperature detected by the first diode-connected BJT; and

producing a first over-temperature signal at an output node of a first threshold detector connected to the current conveyor when the startup bias circuit forms a closed loop to selectively connect the current conveyor to the ground reference voltage only when an emitter current at the first diode-connected BJT device enters a self-turned-on operation region so that the emitter current has a first leakage value until the device junction temperature reaches the self-turned-on operation region which activates the first threshold detector to detect a temperature threshold being reached by the device junction temperature.