Constant voltage circuit and constant current source, amplifier, and power supply circuit using the same
First Claim
1. A constant voltage circuit converting an input voltage into a predetermined constant voltage in accordance with an externally input control signal and outputting the predetermined constant voltage, the constant voltage circuit comprising:
- a constant voltage generator circuit part configured to convert the input voltage into the predetermined constant voltage in accordance with the control signal and output the predetermined constant voltage;
a first capacitor connected to an output end of the constant voltage generator circuit part outputting the constant voltage;
a second capacitor configured to charge the first capacitor; and
a switch circuit part configured to control charging and discharging of the second capacitor in accordance with the control signal, wherein the switch circuit part charges the second capacitor by applying the input voltage thereto and blocks the discharging of the second capacitor to the first capacitor when the constant voltage generator circuit part is caused to stop outputting the predetermined constant voltage by the control signal; and
the switch circuit part stops applying the input voltage to the second capacitor and charges the first capacitor by releasing an electric charge stored in the second capacitor to the first capacitor when the constant voltage generator circuit part is caused to start outputting the predetermined constant voltage by the control signal.
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Accused Products
Abstract
A constant voltage circuit is disclosed that includes a constant voltage generator circuit part converting an input voltage into a predetermined constant voltage in accordance with an externally input control signal and outputting the constant voltage; a first capacitor connected to the output end of the constant voltage generator circuit part; a second capacitor charging the first capacitor; and a switch circuit part controlling charging and discharging of the second capacitor in accordance with the control signal. The switch circuit part charges the second capacitor and blocks the discharging of the second capacitor to the first capacitor when the constant voltage generator circuit part is caused to stop outputting the constant voltage by the control signal, and stops applying the input voltage to the second capacitor and charges the first capacitor when the constant voltage generator circuit part is caused to start outputting the constant voltage by the control signal.
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Citations
25 Claims
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1. A constant voltage circuit converting an input voltage into a predetermined constant voltage in accordance with an externally input control signal and outputting the predetermined constant voltage, the constant voltage circuit comprising:
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a constant voltage generator circuit part configured to convert the input voltage into the predetermined constant voltage in accordance with the control signal and output the predetermined constant voltage;
a first capacitor connected to an output end of the constant voltage generator circuit part outputting the constant voltage;
a second capacitor configured to charge the first capacitor; and
a switch circuit part configured to control charging and discharging of the second capacitor in accordance with the control signal, wherein the switch circuit part charges the second capacitor by applying the input voltage thereto and blocks the discharging of the second capacitor to the first capacitor when the constant voltage generator circuit part is caused to stop outputting the predetermined constant voltage by the control signal; and
the switch circuit part stops applying the input voltage to the second capacitor and charges the first capacitor by releasing an electric charge stored in the second capacitor to the first capacitor when the constant voltage generator circuit part is caused to start outputting the predetermined constant voltage by the control signal. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A constant current source, comprising:
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a constant voltage circuit converting an input voltage into a predetermined constant voltage in accordance with an externally input control signal and outputting the predetermined constant voltage, the constant voltage circuit including;
a constant voltage generator circuit part configured to convert the input voltage into the predetermined constant voltage in accordance with the control signal and output the predetermined constant voltage;
a first capacitor connected to an output end of the constant voltage generator circuit part outputting the constant voltage;
a second capacitor configured to charge the first capacitor; and
a switch circuit part configured to control charging and discharging of the second capacitor in accordance with the control signal, wherein the switch circuit part charges the second capacitor by applying the input voltage thereto and blocks the discharging of the second capacitor to the first capacitor when the constant voltage generator circuit part is caused to stop outputting the predetermined constant voltage by the control signal;
the switch circuit part stops applying the input voltage to the second capacitor and charges the first capacitor by releasing an electric charge stored in the second capacitor to the first capacitor when the constant voltage generator circuit part is caused to start outputting the predetermined constant voltage by the control signal; and
the constant current source generates a constant current by converting the constant voltage output from the constant voltage circuit into current, and outputs the constant current. - View Dependent Claims (8, 9, 10, 11, 12)
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13. An amplifier, comprising:
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a constant current source, the constant current source including a constant voltage circuit converting an input voltage into a predetermined constant voltage in accordance with an externally input control signal and outputting the predetermined constant voltage, the constant voltage circuit including;
a constant voltage generator circuit part configured to convert the input voltage into the predetermined constant voltage in accordance with the control signal and output the predetermined constant voltage;
a first capacitor connected to an output end of the constant voltage generator circuit part outputting the constant voltage;
a second capacitor configured to charge the first capacitor; and
a switch circuit part configured to control charging and discharging of the second capacitor in accordance with the control signal, wherein the switch circuit part charges the second capacitor by applying the input voltage thereto and blocks the discharging of the second capacitor to the first capacitor when the constant voltage generator circuit part is caused to stop outputting the predetermined constant voltage by the control signal;
the switch circuit part stops applying the input voltage to the second capacitor and charges the first capacitor by releasing an electric charge stored in the second capacitor to the first capacitor when the constant voltage generator circuit part is caused to start outputting the predetermined constant voltage by the control signal; and
the constant current source supplies bias current to an amplifier circuit by generating a constant current by converting the constant voltage output from the constant voltage circuit into current. - View Dependent Claims (14, 15, 16, 17, 18, 19)
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20. A power supply circuit, comprising:
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an amplifier, the amplifier including a constant current source, the constant current source including a constant voltage circuit converting an input voltage into a predetermined constant voltage in accordance with an externally input control signal and outputting the predetermined constant voltage, the constant voltage circuit including;
a constant voltage generator circuit part configured to convert the input voltage into the predetermined constant voltage in accordance with the control signal and output the predetermined constant voltage;
a first capacitor connected to an output end of the constant voltage generator circuit part outputting the constant voltage;
a second capacitor configured to charge the first capacitor; and
a switch circuit part configured to control charging and discharging of the second capacitor in accordance with the control signal, wherein the switch circuit part charges the second capacitor by applying the input voltage thereto and blocks the discharging of the second capacitor to the first capacitor when the constant voltage generator circuit part is caused to stop outputting the predetermined constant voltage by the control signal;
the switch circuit part stops applying the input voltage to the second capacitor and charges the first capacitor by releasing an electric charge stored in the second capacitor to the first capacitor when the constant voltage generator circuit part is caused to start outputting the predetermined constant voltage by the control signal;
the constant current source supplies bias current to an amplifier circuit by generating a constant current by converting the constant voltage output from the constant voltage circuit into current;
the amplifier controls an operation of a transistor connected to an input terminal and an output terminal so that a voltage at the output terminal is a predetermined voltage; and
the power supply circuit converts the voltage input to the input terminal into a predetermined voltage and outputs the predetermined voltage from the output terminal. - View Dependent Claims (21, 22, 23, 24, 25)
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Specification