# US 7,746,165 B1 · Voltage selecting circuit, voltage providing circuit utilizing the voltage selecting circuit, and signal delaying system utilizing the voltage providing circuit

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- Number: US 7,746,165 B1
- Document ID: US7746165B1
- Status: Granted
- Kind: B1
- Application number: 12/357,376
- Filed: 2009-01-21
- Published: 2010-07-08
- Granted: 2010-06-29
- Earliest claimed: 2009-01-05
- Assignees: Nanya Technology Corporation
- Inventors: Chih-Jen Chen
- Web page: https://patentgrep.com/patent/US7746165B1

## CPC

- G05F 1/56: using semiconductor devices in series with the load as final control devices (G05F1/461 takes precedence)
- G11C 7/22: Read-write [R-W] timing or clocking circuits; Read-write [R-W] control signal generators or management
- G11C 7/222: {Clock generating, synchronizing or distributing circuits within memory device}
- G11C 11/406: Management or control of the refreshing or charge-regeneration cycles
- G11C 11/40615: {Internal triggering or timing of refresh, e.g. hidden refresh, self refresh, pseudo-SRAMs}
- G11C 11/4074: Power supply or voltage generation circuits, e.g. bias voltage generators, substrate voltage generators, back-up power, power control circuits
- G11C 11/4076: Timing circuits (for regeneration management G11C11/406)
- G11C 2211/4065: Low level details of refresh operations
- G11C 2211/4067: Refresh in standby or low power modes
- G05F: SYSTEMS FOR REGULATING ELECTRIC OR MAGNETIC VARIABLES
- G11C: STATIC STORES (semiconductor memory devices H10B)

## Abstract

A voltage providing circuit includes: a first voltage providing circuit, for generating a first voltage; a switch device, for receiving a first voltage; a second voltage providing circuit, for providing a second voltage; a control circuit, for controlling the switch device and the second voltage providing circuit, wherein in a first mode, the control circuit turns off the switch device for allowing a target device to receive the second voltage, and in a second mode, the control circuit turns on the switch device and stops the second voltage providing circuit from providing the second voltage such that the target device can receive the first voltage; and an adjusting circuit, for providing a reference voltage to the first voltage providing circuit according to the first voltage and the second voltage for changing the first voltage, thereby making the first voltage substantially equal to the second voltage.

## Claims

### Claim 1

A voltage providing circuit, comprising:
a first voltage providing circuit, for providing a first voltage;
a switch element, for receiving the first voltage;
a second voltage providing circuit, for providing a second voltage;
a control circuit, for controlling the switch element and the second voltage providing circuit, wherein in a first mode, the control circuit turns off the switch element for allowing a target apparatus to receive the second voltage, and in a second mode, the control circuit turns on the switch element, and stops the second voltage providing circuit from providing the second voltage to therefore provide the first voltage to the target apparatus; and
an adjusting circuit, coupled to the first voltage providing circuit and the second voltage providing circuit, for providing a reference voltage to the first voltage providing circuit for altering the first voltage, according to the first voltage and the second voltage, thereby making the first voltage substantially equal to the second voltage.

### Claim 2 (depends on 1)

The voltage providing circuit of claim 1, wherein the target apparatus is a delay locked loop circuit, and the second voltage is for controlling a delay time of the delay locked loop circuit.

### Claim 3 (depends on 2)

The voltage providing circuit of claim 2, wherein the delay locked loop circuit is utilized in a memory, the first mode corresponds to a normal mode in which the memory operates, and the second mode corresponds to a power down mode or a self refresh mode in which the memory operates.

### Claim 4 (depends on 1)

The voltage providing circuit of claim 1, wherein the adjusting circuit provides a higher reference voltage when the first voltage is higher than the second voltage.

### Claim 5 (depends on 4)

The voltage providing circuit of claim 4, wherein the adjusting circuit provides a lower reference voltage when the first voltage is lower than the second voltage.

### Claim 6 (depends on 1)

The voltage providing circuit of claim 1, wherein the adjusting circuit comprises:
a comparator, for comparing the first voltage and the second voltage to generate a comparison result;
a counter, coupled to the comparator, for generating a counting signal according to the comparison result; and
a multiplexer, coupled to the counter, for receiving a plurality of candidate voltages and selecting one of the candidate voltages as the reference voltage according to the counting signal.