Internal step-down power supply circuit
First Claim
1. An internal step-down power supply circuit, comprising:
- an internal step-down power-supply output node that outputs an internal step-down power supply potential;
a driver that adjusts an external power-supply potential and outputs the adjusted external power-supply potential to the internal step-down power-supply output node;
a divider circuit that divides a voltage developed at the internal step-down power-supply output node and outputs outputting a divided voltage therefrom; and
a differential amplifier that compares the voltage outputted from the divider circuit and a reference voltage and that outputs a voltage equivalent to twice a predetermined gain, the differential amplifier setting a conductance of each of first transistors that feed a current in response to the reference voltage to twice or more a conductance of each of second transistors that feed a current in response to the voltage outputted from the divider circuit.
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Accused Products
Abstract
An internal step-down power supply circuit improves response performance (transition from a standby state to an active state in particular) of a system, without increasing current consumption. The internal step-down power supply circuit includes an output node for outputting an internal step-down power-supply potential; a driver for adjusting an external power-supply potential VDD and supplying it to the output node; a divider circuit for dividing a voltage developed at the output node and outputting the divided voltage; and a differential amplifier for comparing the divided voltage and a reference voltage. The differential amplifier outputs a voltage equivalent to twice a predetermined gain. The operational amplifier sets the conductance of first transistors for feeding a current responsive to the reference voltage to twice or more the conductance of second transistors for feeding a current responsive to the divided voltage.
20 Citations
18 Claims
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1. An internal step-down power supply circuit, comprising:
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an internal step-down power-supply output node that outputs an internal step-down power supply potential;
a driver that adjusts an external power-supply potential and outputs the adjusted external power-supply potential to the internal step-down power-supply output node;
a divider circuit that divides a voltage developed at the internal step-down power-supply output node and outputs outputting a divided voltage therefrom; and
a differential amplifier that compares the voltage outputted from the divider circuit and a reference voltage and that outputs a voltage equivalent to twice a predetermined gain, the differential amplifier setting a conductance of each of first transistors that feed a current in response to the reference voltage to twice or more a conductance of each of second transistors that feed a current in response to the voltage outputted from the divider circuit. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A step-down power supply circuit, comprising:
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an output node that provides a step-down power supply potential;
a driver, connected to the output node, that provides an electric current from an external power-supply potential source to the output node in accordance with a voltage of an adjustment signal provided thereto;
a divider circuit connected to the output node that divides a voltage at the output node and provides a divided voltage;
a differential amplifier, connected to the driver and the divider circuit, that compares the divided voltage with a reference voltage and that outputs the adjustment signal as having a voltage in accordance with the comparison, the differential amplifier having a first transistor through which a first electric current flows and a second transistor through which a second electric current that is larger than the first electric current flows, wherein the differential amplifier is in a standby mode when the first electric current flows and is in an operation mode when the second electric current flows; and
a speed-up capacitor connected between the output node and an output of the divider circuit. - View Dependent Claims (13, 14, 15)
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16. A step-down power supply circuit, comprising:
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an output node that provides a step-down power supply potential;
a driver, connected to the output node, that provides an electric current from an external power-supply potential source to the output node in accordance with a voltage of an adjustment signal provided thereto;
a divider node;
a divider circuit, connected to the output node and the divider node, that provides a first voltage to the output node and a second voltage to the divider node;
a current mirror amplifier, connected to the driver and the divider node, that compares the second voltage with a reference voltage and outputs the adjustment signal as having a voltage in accordance with the comparison, the current mirror amplifier having a first circuit connected to the divider node, a second circuit connected to the reference voltage, a first current circuit connected to the first and second circuits that provides a standby current to the first and second circuits so that the current mirror amplifier is placed in a standby mode, and a second current circuit connected to the first and second circuits that provides circuit for providing an operational current that is larger than the standby current to the first and second circuits eireuit so that the current mirror amplifier is placed in an operational mode; and
an equalizing circuit connected between the first and second circuits and operable responsive to an operational signal. - View Dependent Claims (17, 18)
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Specification