Semiconductor device and power supply system including the same
AssigneePanasonic Corporation
InventorHiroo YAMAMOTO
Life of this patent
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Abstract
In a semiconductor device, a resistance divider includes a first resistor connecting a supply line to an output node of an analog control signal, a second resistor connecting an output node to ground, a first switching device that is turned on or off by a control circuit, and a second switching device that turns on in response to a voltage equal to the voltage of the supply line. The control circuit turns on the first switching device until a power supply voltage reaches a predetermined voltage, and then turns on or off the first switching device.
Claims12
A semiconductor device that receives a power supply voltage from a power supply device, the power supply voltage having a value in accordance with an analog control signal, the semiconductor device comprising:
- a supply line configured to receive the power supply voltage;
- a resistance divider located between the supply line and ground and configured to divide the power supply voltage by using a resistor to obtain a divided voltage and to output the divided voltage as the analog control signal to the power supply device;
- and
- a control circuit configured to control a voltage division ratio in the resistance divider, wherein
- the resistance divider includes
- one or more first resistors connecting the supply line to an output node of the analog control signal,
- one or more second resistors connecting the output node to the ground,
- one or more first switching devices connected to at least one of the one or more first resistors in parallel, and configured to be turned on or off in response to an output from the control circuit, and
- a second switching device connected to at least one of the one or more second resistors in parallel and configured to be turned on in response to a voltage equal to a voltage of the supply line,
- the control circuit turns on at least one of the one or more first switching devices in a period from when the power supply voltage rises to when the power supply voltage reaches a predetermined voltage, and
- the control circuit starts controlling an on or off state of the one or more first switching devices after the power supply voltage has reached the predetermined voltage.
A semiconductor device that receives a power supply voltage from a power supply device, the power supply voltage having a value in accordance with an analog control signal, the semiconductor device comprising:
- a supply line configured to receive the power supply voltage;
- a resistance divider located between the supply line and ground and configured to divide the power supply voltage by using a resistor to obtain a divided voltage and to output the divided voltage as the analog control signal to the power supply device;
- and
- a control circuit configured to control a voltage division ratio in the resistance divider, wherein
- the resistance divider includes
- one or more first resistors connecting the supply line to an output node of the analog control signal,
- one or more second resistors connecting the output node to the ground, and
- one or more first switching devices connected to at least one of the one or more first resistors or at least one of the one or more second resistors, or connected to at least one of the one or more first resistors and at least one of the one or more second resistors, in parallel, and configured to be turned on or off in response to an output from the control circuit,
- the control circuit turns off all the one or more first switching devices in a period from when the power supply voltage rises to when the power supply voltage reaches a predetermined voltage, and
- the control circuit starts controlling an on or off state of the one or more first switching devices after the power supply voltage has reached the predetermined voltage.
Dependencies are inferred from the claim text.