US 11,867,571 B2
Self-turn-on temperature detector circuit
Ricardo Pureza Coimbra, Campinas (BR); and Mateus Ribeiro Vanzella, Campinas (BR)
Assigned to NXP B.V., Eindhoven (NL)
Filed by NXP B.V., Eindhoven (NL)
Filed on Oct. 1, 2021, as Appl. No. 17/491,744.
Prior Publication US 2023/0108765 A1, Apr. 6, 2023
Int. Cl. G01K 7/01 (2006.01); G01K 15/00 (2006.01); H03K 17/687 (2006.01)
CPC G01K 7/015 (2013.01) [G01K 15/005 (2013.01); H03K 17/6872 (2013.01); G01K 7/01 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A temperature detection device, comprising:
a reference voltage generator configured to generate a reference voltage VREF;
a current conveyor connected to receive first and second bias currents and configured to produce a first over-temperature signal at an output node in response to first and second input voltages VS1, VS2; and
a startup bias circuit configured to selectively connect the current conveyor to ground, comprising:
a first FET device having a gate terminal connected to receive the reference voltage VREF, a drain terminal connected to ground, and a source terminal connected to provide the first input voltage VS1,
a first diode-connected bipolar junction transistor (BJT) device having base and collector terminals connected to ground 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 the second input voltage VS2 in response to variations in a device junction temperature detected by the first diode-connected BJT,
where the startup bias circuit and current conveyor are connected and activated to form a closed loop only when an emitter current at the first diode-connected BJT device enters a self-turned-on operation region, thereby activating the current conveyor to detect a temperature threshold being reached by the device junction temperature.