Switching power supply
First Claim
1. A switching power supply comprising:
- a main circuit having a switching circuit for converting a DC input voltage to an AC voltage and an output circuit for rectifying the AC voltage to generate a DC output voltage;
a control circuit for controlling the operation of the main circuit; and
an abrupt load change detector circuit for detecting an abrupt change in the load current supplied from the main circuit, and abrupt load change detector circuit which includes;
a first filter and a second filter for receiving the output voltage, a time constant of the first filter being different from that of the second filters; and
detection signal generating means for generating an abrupt load change detection signal based on the outputs of the first and second filters, the detection signal generating means which includes a comparator for receiving an output of the first filter at one input terminal and of the second filter at the other input terminal.
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Accused Products
Abstract
The switching power supply comprises a main circuit having a switching circuit for converting a DC input voltage to an AC voltage and an output circuit for rectifying the AC voltage to generate a DC output voltage, a control circuit for controlling the operation of the main circuit, and an abrupt load change detector circuit for detecting an abrupt change in the load current supplied from the main circuit, characterized in that the abrupt load change detector circuit comprises a first filter and a second filter for receiving the output voltage and detection signal generating means for generating an abrupt load change detection signal based on the outputs of the first filter and the second filter. This eliminates a power loss or operation delay caused when a resistor or a current transformer is used to directly detect the output current. Proper use of an abrupt load change detection signal allows dramatic improvement in transient response.
28 Citations
22 Claims
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1. A switching power supply comprising:
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a main circuit having a switching circuit for converting a DC input voltage to an AC voltage and an output circuit for rectifying the AC voltage to generate a DC output voltage;
a control circuit for controlling the operation of the main circuit; and
an abrupt load change detector circuit for detecting an abrupt change in the load current supplied from the main circuit, and abrupt load change detector circuit which includes;
a first filter and a second filter for receiving the output voltage, a time constant of the first filter being different from that of the second filters; and
detection signal generating means for generating an abrupt load change detection signal based on the outputs of the first and second filters, the detection signal generating means which includes a comparator for receiving an output of the first filter at one input terminal and of the second filter at the other input terminal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. The switching power supply comprising:
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a main circuit having a switching circuit for converting a DC input voltage to an AC voltage and an output circuit for rectifying the AC voltage to generate a DC output voltage;
a control circuit for controlling the operation of the main circuit; and
an abrupt load change detector circuit for detecting an abrupt change in the load current supplied from the main circuit, the abrupt load change detector circuit which includes;
a first to third filters for receiving the output voltage;
a first comparator for receiving the output of the first filter at one input terminal and the output of the second filter at the other input terminal thus generating a first abrupt load change detection signal based on these outputs; and
a second comparator for receiving the output of the first filter at one input terminal and the output of the third filter at the other input terminal thus generating a second abrupt load change detection signal based on these outputs. - View Dependent Claims (13, 14)
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15. The switching power supply comprising:
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a main circuit having a switching circuit for converting a DC input voltage to an AC voltage and an output circuit for rectifying the AC voltage to generate a DC output voltage;
a control circuit for controlling the operation of the main circuit; and
an abrupt load change detector circuit for detecting an abrupt change in the load current supplied from the main circuit, the abrupt load change detector circuit which includes;
a first filter and a second filter for receiving the output voltage;
an operational amplifier for amplifying the output voltage level difference between the first and second filters;
a first comparator for activating the first abrupt load change detection signal in response to the output of the operational amplifier which exceeds the first threshold voltage; and
a second comparator for activating the second abrupt load change detection signal in response to the output of the operational amplifier which exceeds the second threshold voltage. - View Dependent Claims (16, 17, 18, 19, 20, 21, 22)
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Specification