Semiconductor device having on-chip oscillator for producing clock signal
AssigneeRenesas Electronics Corporation
InventorsTsukasa Oishi, Katsuyoshi Mitsui, Naoki Otani
Life of this patent
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Abstract
A semiconductor device contrived to prevent a reference voltage and a reference current which are supplied to a high speed OCO from varying with a change in ambient temperature and/or a change in an external power supply voltage and to reduce the circuit area of a power supply module. The high speed OCO outputs a high speed clock whose magnitude is determined by the reference current and the reference voltage. A logic unit adjusts the values of the reference current and reference voltage, according to the reference voltage and reference current trimming codes related to detected ambient temperature and operating voltage.
Claims8
A semiconductor device comprising:
- a first on-chip oscillator which receives a reference current and a reference voltage and outputs a clock signal with a first frequency whose magnitude is determined by said reference current and said reference voltage;
- a temperature sensor which detects an ambient temperature of said first on-chip oscillator;
- a voltage sensor which detects a value of an operating voltage of said first on-chip oscillator;
- a power supply module which includes a reference circuit for generating a primary reference voltage and generates said reference voltage, said reference current, and the operating voltage of said first on-chip oscillator, based on the primary reference voltage which is output by said reference circuit;
- a storage unit which stores a table specifying trimming codes for said reference voltage and said reference current, related to an ambient temperature of said first on-chip oscillator and an operating voltage of said first on-chip oscillator;
- and
- a logic unit which reads trimming codes for said reference voltage and said reference current, the trimming codes being related to the detected ambient temperature and operating voltage, and adjusts the values of said reference current and said reference voltage, according to the read trimming codes.
Dependencies are inferred from the claim text.