Invention Grant
- Patent Title: Differential temperature sensor with sensitivity set by current-mirror and resistor ratios without limiting DC bias
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Application No.: US14468554Application Date: 2014-08-26
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Publication No.: US09638584B2Publication Date: 2017-05-02
- Inventor: Chun Fai Wong , Leung Ling (Alan) Pun , Kam Hung Chan , Kwok Kuen (David) Kwong
- Applicant: Hong Kong Applied Science & Technology Research Institute Company Limited
- Applicant Address: HK Hong Kong
- Assignee: Hong Kong Applied Science and Technology Research Institute Company Limited
- Current Assignee: Hong Kong Applied Science and Technology Research Institute Company Limited
- Current Assignee Address: HK Hong Kong
- Agency: gPatent LLC
- Agent Stuart T. Auvinen
- Main IPC: G01K7/00
- IPC: G01K7/00 ; G01K7/01 ; H01L35/32

Abstract:
A differential on-chip temperature sensor circuit can be implemented in a standard complementary metal-oxide-semiconductor (CMOS) process using PNP transistors. A pair of transistors have collector currents that are sensitive to voltage, both directly and due to saturation currents. A scaling resistor connects to the emitter of one transistor and its voltage compared to the other transistor's emitter voltage by an error amplifier that generates a bias voltage to current sources that are proportional to absolute temperature since the saturation current sensitivity is subtracted out. The current is mirrored to sink current through a multiplier resistor from an output. An amplifier connected across the multiplier resistor compares a reference voltage to set the DC bias independent of temperature sensitivity. The temperature sensitivity is proportional to the ratio of the multiplier resistor and the scaling resistor, and is multiplied by a mirroring factor. A differential output is provided.
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