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

Claim 18:
19. A device, comprising:
a current conveyor circuit connected to receive first and second bias currents and comprising a current mirror and a threshold detector connected to a first over-temperature output node; and
a startup bias circuit connected between the current conveyor circuit and a ground reference voltage to receive a reference voltage VREF, the startup bias circuit comprising:
a first PFET device having a gate terminal connected to 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 circuit,
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 PFET 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 circuit in response to variations in a device junction temperature detected by the first diode-connected BJT device,

where the startup bias circuit is configured to generate a leakage current at the emitter terminal of the first diode-connected BJT device at low device junction temperatures until the device junction temperature reaches a self-turned-on operation region which activates the startup bias circuit to form a closed loop between the current conveyor circuit and ground reference voltage so that the current conveyor circuit is activated to produce a first over-temperature signal at the first over-temperature output node when the threshold detector detects that the device junction temperature reaches a temperature threshold.