Recirculating MOS charge pump
First Claim
Patent Images
1. A circuit for increasing a power supply voltage from a power supply source and providing a boosted output voltage at an output terminal, comprising:
- diode means coupled between a first node and a supply terminal adapted to receive the power supply voltage, said diode means having a threshold voltage and preventing current flow from the first node to the supply terminal;
first charge storage means coupled to the output terminal for selectively storing the power supply voltage and a boost voltage to provide the boosted output voltage; and
transistor coupling means having a control electrode, a first current electrode coupled to the first node, and a second current electrode coupled to the output terminal, and a threshold voltage associated therewith;
wherein the improvement comprises;
compensation means coupled between the first node and the control electrode of the transistor coupling means, for providing a control voltage to the control electrode sufficiently above the threshold voltage of the transistor coupling means so as to reduce the effective threshold voltage drop between the first node and the output terminal to substantially zero volts.
2 Assignments
0 Petitions
Accused Products
Abstract
A charge pump which can operate at low supply voltages is provided. The charge pump recirculates charge in response to an alternating clock signal which alternates the charge across a plurality of charge storage devices. Charge recirculation is used to compensate for threshold voltage drops associated with diodes or diode-configured transistors used to implement the charge pump. As a result, voltage amplification can occur in the charge pump even for small power supply values.
-
Citations
12 Claims
-
1. A circuit for increasing a power supply voltage from a power supply source and providing a boosted output voltage at an output terminal, comprising:
-
diode means coupled between a first node and a supply terminal adapted to receive the power supply voltage, said diode means having a threshold voltage and preventing current flow from the first node to the supply terminal; first charge storage means coupled to the output terminal for selectively storing the power supply voltage and a boost voltage to provide the boosted output voltage; and transistor coupling means having a control electrode, a first current electrode coupled to the first node, and a second current electrode coupled to the output terminal, and a threshold voltage associated therewith; wherein the improvement comprises; compensation means coupled between the first node and the control electrode of the transistor coupling means, for providing a control voltage to the control electrode sufficiently above the threshold voltage of the transistor coupling means so as to reduce the effective threshold voltage drop between the first node and the output terminal to substantially zero volts. - View Dependent Claims (2, 3, 4, 5)
-
-
6. A charge pump circuit for boosting a power supply voltage to provide a boosted output voltage, comprising:
-
a diode configured transistor having a first current electrode and a control electrode connected together and coupled to a terminal for receiving the power supply voltage, and a second current electrode connected to a first node for supplying a primary voltage at the first node, said diode configured transistor having a first threshold voltage drop associated therewith; first capacitance means having a first electrode coupled to the first node and a second electrode for selectively receiving a clock signal voltage, said capacitance means boosting the primary voltage at the first node to a secondary voltage; first compensation means coupled in parallel with the diode configured transistor for compensating for the first threshold voltage drop so that the primary voltage substantially equals the power supply voltage; output capacitance means for selectively storing the secondary voltage to provide the boosted output voltage; transistor coupler means having a second threshold voltage drop associated therewith, said transistor coupler means having a control electrode and current conducting electrodes which selectively couple the first node to the output capacitance means; and second compensation means coupled between the control electrode and a predetermined one of the current conducting electrodes of the transistor coupler means for compensating for the second threshold voltage drop so that the boosted output voltage substantially equals the secondary voltage at the first node. - View Dependent Claims (7, 8, 9, 10)
-
-
11. A method of providing a boosted output voltage from a power supply voltage, comprising the steps of:
-
coupling a power supply voltage terminal to a first node via a diode means having a first threshold voltage drop associated therewith; coupling charge storage means to the first node for selectively boosting the first node'"'"'s voltage potential to a predetermined voltage potential; selectively coupling the first node to an output charge storage means via a coupling device having a second threshold voltage drop associated therewith; and compensating for the second threshold voltage drop so that the voltage potential coupled to the output charge storage means substantially equals the voltage potential of the first node. - View Dependent Claims (12)
-
Specification