Switching regulator with lower transistor capable of two states of ON or low current
AssigneeRichtek Technology Corporation
InventorsNien-Hui Kung, Kwan-Jen Chu
Life of this patent
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Abstract
The present invention discloses a switching regulator, which comprises: a first and a second transistors electrically connected with each other; a pulse width modulation control circuit for turning ON and OFF the first transistor and turning ON the second transistor; and a current source control circuit for controlling the second transistor so that the second transistor becomes a current source, wherein the second transistor has only two states: ON and low current, and wherein when the first transistor is ON, the second transistor is in the low current state; and when the first transistor is OFF, the second transistor is ON or in the low current state.
Claims20
A switching regulator comprising:
- a first and a second transistors electrically connected with each other;
- a pulse width modulation control circuit for turning ON and OFF the first transistor and turning ON the second transistor;
- and
- a current source control circuit for controlling the second transistor so that the second transistor becomes a current source,
- wherein the second transistor has only two states:
- ON or low current, in which when the first transistor is ON, the second transistor is in the low current state;
- and when the first transistor is OFF, the second transistor is ON or in the low current state, and
- wherein other than the time when the second transistor is ON, the second transistor is in the low current state, controlled by the current source control circuit.
A control circuit for a switching regulator having a first and a second transistors electrically connected with each other, the control circuit comprising:
- a current source control circuit for controlling the second transistor to operate only in two states of ON or low current:
- to be ON or in the low current state when the first transistor is OFF, and to be in the low current state when the first transistor is ON:
- in the low current state the amount of current passing through the second transistor being higher than or equal to 1 μA (micro-ampere),
- wherein other than the time when the second transistor is ON, the second transistor is in the low current state.
A method for controlling a switching regulator, comprising the steps of:
- providing a switching regulator having a first and a second transistors electrically connected with each other, the second transistor operating only in two states of ON or low current;
- and
- when the first transistor is OFF, controlling the second transistor to be ON or in the low current state, and when the first transistor is ON, controlling the second transistor to be in the low current state;
- in the low current state the amount of current passing through the second transistor being higher than or equal to 1 μA (micro-ampere),
- wherein other than the time when the second transistor is ON, the second transistor is in the low current state.
Dependencies are inferred from the claim text.