# US 7,609,041 B2 · Automatic voltage control circuit and method thereof

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- Number: US 7,609,041 B2
- Document ID: US7609041B2
- Status: Granted
- Kind: B2
- Application number: 11/772,233
- Filed: 2007-07-01
- Published: 2008-05-29
- Granted: 2009-10-27
- Earliest claimed: 2006-07-06
- Assignees: Realtek Semiconductor Corp.
- Inventors: Meng-Han Hsieh; Chi-Shun Weng
- Web page: https://patentgrep.com/patent/US7609041B2

## CPC

- G06F 1/3203: Power management, i.e. event-based initiation of a power-saving mode
- G06F 1/324: by lowering clock frequency
- G06F 1/3296: by lowering the supply or operating voltage
- Y02D 10/00: Energy efficient computing, e.g. low power processors, power management or thermal management
- G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N)
- Y02D: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN INFORMATION AND COMMUNICATION TECHNOLOGIES [ICT], I.E. INFORMATION AND COMMUNICATION TECHNOLOGIES AIMING AT THE REDUCTION OF THEIR OWN ENERGY USE

## Abstract

An automatic voltage control circuit controls a power supply unit to adjust a supply voltage provided by the power supply unit. The automatic voltage control circuit includes an oscillating unit, a frequency-comparing unit, and a control unit. The oscillating unit generates an oscillating signal. The frequency-comparing unit compares the oscillating frequency of the oscillating signal with at least one predetermined threshold frequency. The control unit controls the power supply unit to adjust the supply voltage according to the comparing result generated by the frequency-comparing unit.

## Claims

### Claim 1

An automatic voltage control circuit for controlling a power supply unit to adjust a supply voltage provided by the power supply unit, comprising:
a ring oscillator, coupled to the power supply unit, for generating an oscillating signal, wherein the ring oscillator comprises a plurality of inverters, and at least one of the inverters comprises a NOR gate or a NAND gate;
a frequency-comparing unit, coupled to the oscillating unit, for comparing an oscillating frequency of the oscillating signal with at least one predetermined threshold frequency to generate a comparison result; and
a control unit, coupled to the frequency-comparing unit and the power supply unit, for controlling the power supply unit to adjust the supply voltage according to the comparison result.

### Claim 2 (depends on 1)

The circuit of claim 1, wherein the frequency-comparing unit comprises:
a counter, coupled to the oscillating unit, for calculating an oscillating number of the oscillating signal during a period of time to generate a counting value; and
a comparison unit, coupled to the counter and the control unit, for comparing the counting value with at least one predetermined threshold value, wherein the predetermined threshold value corresponds to the predetermined threshold frequency.

### Claim 3 (depends on 1)

The circuit of claim 1, wherein if the oscillating frequency is greater than a first predetermined threshold frequency of the predetermined threshold frequencies, the control unit controls the power supply unit to decrease the supply voltage.

### Claim 4 (depends on 1)

The circuit of claim 1, wherein if the oscillating frequency is less than a second predetermined threshold frequency of the predetermined threshold frequencies, the control unit controls the power supply unit to increase the supply voltage.

### Claim 5 (depends on 1)

The circuit of claim 1, wherein the control unit comprises a logic circuit.

### Claim 6

An automatic voltage control circuit for controlling a power supply unit to adjust a supply voltage provided by the power supply unit, comprising:
a plurality of ring oscillators, coupled to the power supply unit, for generating a plurality of oscillating signals, wherein each ring oscillator comprises a plurality of inverters, and at least one of the inverters comprise a NOR gate or a NAND gate;
a plurality of frequency-comparing units, each of the plurality of frequency-comparing units respectively coupled to one of the oscillating units, for comparing an oscillating frequency of the each oscillating signal with at least one corresponding predetermined threshold frequency to generate a comparison result; and
at least one control unit, coupled to the frequency-comparing units and the power supply unit, for controlling the power supply unit to adjust the supply voltage according to the comparison result.

### Claim 7 (depends on 6)

The circuit of claim 6, wherein the each frequency-comparing unit comprises:
a counter, coupled to the corresponding oscillating unit, for calculating an oscillating number of the oscillating signal during a period of time to generate a counting value; and
a comparison unit, coupled to the counter and the control unit, for comparing the counting value with at least one predetermined threshold value, wherein the predetermined threshold value corresponds to the predetermined threshold frequency.

### Claim 8 (depends on 6)

The circuit of claim 6, wherein if all the oscillating frequencies generated are greater than the corresponding predetermined threshold frequencies respectively, the control unit controls the power supply unit to decrease the supply voltage.

### Claim 9 (depends on 6)

The circuit of claim 6, wherein if at least one of the oscillating frequencies generated is less than one of the predetermined threshold frequencies, the control unit controls the power supply unit to increase the supply voltage.

### Claim 10 (depends on 6)

The circuit of claim 6, wherein at least one of the inverters comprises a CMOS inverter.