Circuit technique for improved current matching in charge pump PLLS
AssigneeCypress Semiconductor Corporation
InventorSatish C. Saripella
Life of this patent
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Abstract
An apparatus comprising a pullup circuit, a pulldown circuit, and a control circuit. The pullup circuit may be configured to receive a first and second control signal. The pulldown circuit may be configured to receive a third and fourth control signal. The control circuit may be configured to generate the first, second, third and fourth control signals. The control circuit may comprise (i) a first and second control device coupled between the first and second control signals and a supply and (ii) a third and fourth control device coupled between the third and fourth control signals and the supply.
Claims18
An apparatus comprises:
- a pullup circuit configured to receive a first and second control signal;
- a pulldown circuit configured to receive a third and fourth control signal;
- and
- a control circuit configured to generate said first, second, third and fourth control signals, wherein said control circuit comprises (i) a first control device configured to generate said first control signal in response to a supply voltage, (ii) a second control device configured to generate said second control signal in response to said first control signal and said supply voltage, (iii) a third control device configured to generate said third control signal in response to said supply voltage and (iv) a fourth control device configured to generate said fourth control signal in response to said third control signal and said supply voltage.
An apparatus comprises:
- a pullup circuit configured to receive a first and second control signal;
- a pulldown circuit configured to receive a third and fourth control signal;
- and
- means for generating said first, second, third and fourth control signals, wherein said generating means comprises (i) a first control device configured to generate said first control signal in response to a supply voltage, (ii) a second control device configured to generate said second control signal in response to said first control signal and said supply voltage, (iii) a third control device configured to generate said third control signal in response to said supply voltage and (iv) a fourth control device configured to generate said fourth control signal in response to said third control signal and said supply voltage.
A method for generating a constant current comprising the steps of:
- (A) sourcing a current in response to a first and second control signal;
- (B) sinking a current in response to a third and fourth control signal;
- (C) generating (i) said first control signal in response to a supply voltage and (ii) said second control signal in response to said first control signal and said supply voltage;
- and
- (D) generating (i) said third control signal in response to said supply voltage and (ii) said fourth control signal in response to said third control signal and said supply voltage.
Dependencies are inferred from the claim text.