Semiconductor device, load drive system and method of detecting inductor current
AssigneeRenesas Electronics Corporation
InventorHideyuki Tajima
Life of this patent
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Abstract
A monitor circuit monitors a gate potential applied to a gate of a high-side transistor or monitors an output potential generated at an output terminal and generates either one or both of a high-side sampling timing and a high-side holding timing based on the monitored result. A current detection circuit detects an inductor current flowing in an inductor and generates a first detection voltage proportional to the inductor current. A sample-and-hold circuit starts a sampling operation of the first detection voltage in response to the high-side sampling timing and starts a holding operation of the first detection voltage in response to the high-side holding timing so as to output a second detection voltage.
Claims20
A semiconductor device comprising:
- a high-side transistor coupled between a high-potential side power-supply potential and an output terminal, and allowing power to be accumulated in an inductor via the output terminal when the high-side transistor is controlled to be ON;
- a PWM signal-generating circuit generating a PWM signal that controls ON/OFF of the high-side transistor;
- a monitor circuit monitoring a high-side control input potential applied to a control input node of the high-side transistor or monitoring an output potential generated at the output terminal, and generating either one or both of a high-side sampling timing and a high-side holding timing based on a monitored result;
- a current detection circuit detecting an inductor current flowing in the inductor, and generating a first detection voltage proportional to the inductor current;
- and
- a sample-and-hold circuit 1) starting a sampling operation of the first detection voltage in response to the high-side sampling timing, 2) performing, while the high-side transistor is ON, the sampling operation that started in response to the high-side sampling timing, and 3) starting a holding operation of the first detection voltage in response to the high-side holding timing so as to output a second detection voltage.
A load drive system comprising:
- an inductor coupled to an output terminal and serving as a load;
- a high-side transistor coupled between a high-potential side power-supply potential and the output terminal, and allowing power to be accumulated in the inductor via the output terminal when the high-side transistor is controlled to be ON;
- a PWM signal-generating circuit generating a PWM signal that controls ON/OFF of the high-side transistor;
- a monitor circuit monitoring a high-side control input potential applied to a control input node of the high-side transistor or monitoring an output potential generated at the output terminal, and generating either one or both of a high-side sampling timing and a high-side holding timing based on a monitored result;
- a current detection circuit detecting an inductor current flowing in the inductor, and generating a first detection voltage proportional to the inductor current;
- and
- a sample-and-hold circuit 1) starting a sampling operation of the first detection voltage in response to the high-side sampling timing, 2) performing, while the high-side transistor is turned ON, the sampling operation that started in response to the high-side sampling timing, and 3) starting a holding operation of the first detection voltage in response to the high-side holding timing so as to output a second detection voltage.
A method of detecting an inductor current by using a load drive system that includes:
- an inductor coupled to an output terminal and serving as a load;
- a high-side transistor coupled between a high-potential side power-supply potential and the output terminal, having ON/OFF controlled by a PWM signal, and allowing power to be accumulated in the inductor via the output terminal when the high-side transistor is controlled to be ON;
- and
- a current detection unit detecting the inductor current flowing in the inductor by sampling and holding operations,
- wherein the current detection unit performs:
- a first step of monitoring a high-side control input potential applied to a control input node of the high-side transistor or monitoring an output potential generated at the output terminal,
- a second step of generating either one or both of a high-side sampling timing and a high-side holding timing based on a monitored result obtained in the first step, and
- a third step of 1) starting the sampling operation in response to the high-side sampling timing, 2) performing, while the high-side transistor is turned ON, the sampling operation that started in response to the high-side sampling timing, and 3) starting the holding operation in response to the high-side holding timing.
Dependencies are inferred from the claim text.