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US 11,686,748 B2Granted
Current detecting circuit, current detecting system, and power source circuit
AssigneesKabushiki Kaisha Toshiba, Toshiba Electronic Devices & Storage Corporation
InventorHideaki Majima
Life of this patent
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Abstract
According to an embodiment, a current detecting circuit includes: a normally-OFF type second switching element that is cascode-connected to a normally-ON type first switching element that includes a drain for outputting an output current; a normally-OFF type third switching element that is connected in parallel to the second switching element and whose drain is connected to a variable current source; and a comparison circuit that outputs a detection signal in accordance with a comparison result between a drain voltage of the second switching element and a drain voltage of the third switching element.
Claims20
A current detecting circuit comprising:
- a normally-ON type first switching element that includes a source, a drain, and a gate;
- a normally-OFF type second switching element that includes a drain connected to the source of the first switching element, a source connected to a reference electric potential, and a gate;
- a normally-OFF type third switching element that includes a source connected to the source of the second switching element, a drain connected to a current source whose current value changes in response to a control signal, and a gate to which a voltage applied to the gate of the second switching element is applied at a current detection time;
- and
- a comparison circuit configured to:
- compare a drain voltage of the second switching element and a drain voltage of the third switching element with each other;
- and
- output a detection signal.
5 more elements
A current detecting system comprising:
- a current detecting circuit including:
- a normally-ON type first switching element that includes a source, a drain, and a gate;
- a normally-OFF type second switching element that includes a drain connected to the source of the first switching element, a source connected to a reference electric potential, and a gate;
- a normally-OFF type third switching element that includes a source connected to the source of the second switching element, a drain connected to a current source whose current value changes in response to a control signal, and a gate to which a voltage applied to the gate of the second switching element is applied at a current detection time;
- and
- a comparison circuit configured to:
- compare a drain voltage of the second switching element and a drain voltage of the third switching element with each other;
- and
- output a detection signal;
- a control circuit that generates basic data of the control signal;
- a first isolator configured to:
- electrically insulate the control circuit and the current detecting circuit from each other;
- and
- supply a signal based on the basic data to the current detecting circuit;
- and
- a second isolator configured to:
- electrically insulate the comparison circuit and the control circuit from each other;
- and
- supply the detection signal to the control circuit.
16 more elements
A power source circuit comprising:
- a first input terminal and a second input terminal to which an alternating-current power supply is connected;
- a first output terminal and a second output terminal;
- a normally-ON type first switching element that includes a drain connected to the first input terminal, a source, and a gate;
- a normally-OFF type second switching element that includes a drain connected to the source of the first switching element, a source connected to the second output terminal, and a gate;
- a normally-OFF type third switching element that includes a source connected to the source of the second switching element, a drain connected to a first current source whose current value changes in response to a first control signal, and a gate to which a voltage applied to the gate of the second switching element is applied at a current detection time;
- a first comparison circuit that compares a drain voltage of the second switching element and a drain voltage of the third switching element with each other;
- a normally-ON type fourth switching element that includes a drain connected to the first output terminal, a source, and a gate;
- a normally-OFF type fifth switching element that includes a drain connected to the source of the fourth switching element, a source connected to the first input terminal, and a gate;
- a normally-OFF type sixth switching element that includes a source connected to the source of the fifth switching element, a drain connected to a second current source whose current value changes in response to a second control signal, and a gate to which a voltage applied to the gate of the fifth switching element is applied at a current detection time;
- a second comparison circuit that compares a drain voltage of the fifth switching element and a drain voltage of the sixth switching element with each other;
- a drive circuit that generates, in response to output signals of the first comparison circuit and the second comparison circuit, a drive signal for controlling turning ON/OFF of the first to the sixth switching elements;
- a first rectifier element connected between the second input terminal and the first output terminal;
- a second rectifier element connected between the second input terminal and the second output terminal;
- and
- a capacitor connected between the first output terminal and the second output terminal.
12 more elements
Dependencies are inferred from the claim text.