OUTPUT VOLTAGE CONTROL CIRCUIT FOR MODULAR POWER SUPPLIES

• US 20100001699A1
• Filed: 07/01/2009
• Published: 01/07/2010
• Est. Priority Date: 07/02/2008
• Status: Abandoned Application

• Current Assignee: Murata Power Solutions Incorporated (Murata Manufacturing Co Limited)
• Original Assignee: Murata Power Solutions Incorporated (Murata Manufacturing Co Limited)
• Inventors: DRAGOJEVIC, Milan
• Application Number:
  US12/496,600
• Publication Number:
  US 20100001699A1
• Time in Patent Office: Days
• US Class Current: 323/234
• CPC Class Codes: H02M 3/156 with automatic control of output voltage or current, e.g. switching regulators
• CPC Class Codes: H02M 3/157 with digital control

Abstract

A method for adjusting an output voltage of a module includes providing a digital reference voltage, converting the digital reference voltage to an analog reference voltage, comparing the output voltage and the analog reference voltage, controlling the module based upon a result of the step of comparing the output voltage and the analog reference voltage such that the output voltage corresponds to the analog reference voltage, and adjusting the digital reference voltage. An increase in the digital reference voltage causes a corresponding increase in the output voltage, and a decrease in the digital reference voltage causes a corresponding decrease in the output voltage.

Claims

1. A method of adjusting an output voltage of a module comprising:

providing a digital reference voltage;

converting the digital reference voltage to an analog reference voltage;

comparing the output voltage and the analog reference voltage;

controlling the module based upon a result of the step of comparing the output voltage and the analog reference voltage such that the output voltage corresponds to the analog reference voltage; and

adjusting the digital reference voltage;

wherein

an increase in the digital reference voltage causes a corresponding increase in the output voltage; and

a decrease in the digital reference voltage causes a corresponding decrease in the output voltage.

2. A method according to claim 1, wherein the output voltage satisfies the following equation:

Vout=k×

Nadj

where Vout is the output voltage, Nadj is an integer selected during the adjusting step, and k is a constant.

3. A method according to claim 2, wherein the voltage output is connected to a voltage divider with a first resistor and a second resistor;

and

the constant k satisfies the following equation;

4. A method according to claim 1, wherein the adjusting step includes a step of fine adjusting and a step of coarse adjusting;

the digital reference voltage includes a coarse digital reference voltage and a fine coarse digital reference voltage;

the output voltage satisfies the following equation;

Vout=k1×

Nadjc+k2×

Nadjf

where Vout is the output voltage, Nadjc is an integer selected during the coarse adjusting step, Nadjf is an integer selected during the fine adjusting step, and k1, k2 are constants.

5. A method according to claim 4, wherein the voltage output is connected to a voltage divider with a first resistor and a second resistor;

the coarse digital reference voltage is connected to a first RC filter including a third resistor;

the fine digital reference voltage is connected to a second RC filter including a fourth resistor; and

the constants k1 and k2 satisfy the following equations;

6. A method of adjusting an output voltage of a module comprising:

providing a digital reference voltage and a first analog reference voltage;

converting the digital reference voltage to a second analog reference voltage;

combining the second analog reference voltage and the output voltage;

comparing the first analog reference voltage and the combined second analog reference voltage and output voltage;

controlling the module based upon a result of the step of comparing the first analog reference voltage and the combined second analog reference voltage and output voltage so the output voltage corresponds to the second analog reference voltage;

adjusting the digital reference voltage;

wherein

an increase in the digital reference voltage causes a corresponding decrease in the output voltage; and

a decrease in the digital reference voltage causes a corresponding increase in the output voltage.

7. A method according to claim 6, wherein the output voltage satisfies the following equation:

Vout=k1×

Vref−

k2×

Nadj

where Vout is the output voltage, Vref is the first analog reference voltage, Nadj is an integer selected during the adjusting step, and k1 and k2 are constants.

8. A method according to claim 7, wherein the voltage output is connected to a voltage divider with a first resistor and a second resistor connected in series between ground and the output voltage;

the second analog reference voltage is connected to a node between the first resistor and the second resistor through a third resistor; and

the constants k1 and k2 satisfy the following equations;

9. A method according to claim 6, wherein the adjusting step includes a step of fine adjusting and a step of coarse adjusting;

the digital reference voltage includes a coarse digital reference voltage and a fine coarse digital reference voltage; and

the output voltage satisfies the following equation;

Vout=k1×

Vref−

(k2×

Nadjc+k3×

Nadjf)

where Vout is the output voltage, Nadjc is an integer selected during the coarse adjusting step, Nadjf is an integer selected during the fine adjusting step, and k1, k2, and k3 are constants.

10. A method according to claim 9, wherein the voltage output is connected to a voltage divider with a first resistor and a second resistor connected in series between ground and the output voltage;

the second analog reference voltage is connected to a node between the first resistor and the second resistor through a third resistor;

the coarse digital reference voltage is connected to a first RC filter including a fourth resistor;

the fine digital reference voltage is connected to a second RC filter including a fifth resistor; and

the constants k1, k2, and k3 satisfy the following equations;

11. A power system comprising:

a module arranged to provide an output voltage; and

a control circuit connected to the module including;

a manually-adjustable reference voltage circuit arranged to convert an adjustable digital reference voltage to an adjustable analog reference voltage; and

an error amplifier arranged to compare the output voltage and the adjustable analog reference voltage and to provide a control signal to the module based upon the comparison of the output voltage and the adjustable analog reference voltage;

wherein the control circuit and the module are arranged such that;

an increase in the adjustable digital reference voltage causes a corresponding increase in the output voltage; and

a decrease in the adjustable digital reference voltage causes a corresponding decrease in the output voltage.

12. A power system according to claim 11, further comprising:

a first push-button connected to the manually-adjustable reference voltage circuit that, when manually activated, increases the adjustable digital reference voltage; and

a second push-button connected to the manually-adjustable reference voltage circuit that, when manually activated, decreases the adjustable digital reference voltage.

13. A power system according to claim 11, wherein the manually-adjustable reference voltage circuit includes:

a microcontroller including;

a non-volatile memory arranged to store a value corresponding to the adjustable digital reference voltage; and

a digital pulse width modulator arranged to output the adjustable digital reference voltage; and

a low-pass filter is arranged to receive the adjustable digital reference voltage from the digital pulse width modulator and arranged to output the adjustable analog reference voltage.

14. A power system according to claim 11, wherein the adjustable digital reference voltage includes a coarse adjustable digital reference voltage and a fine adjustable fine digital reference voltage;

the manually-adjustable reference voltage circuit includes;

a microcontroller including;

a non-volatile memory arranged to store a value corresponding to the adjustable digital reference voltage;

a first digital pulse width modulator arranged to output the coarse adjustable digital reference voltage; and

a second digital pulse width modulator arranged to output the fine adjustable digital reference voltage; and

a low-pass filter is arranged to receive the coarse adjustable digital reference voltage from the first digital pulse width modulator, to receive the fine adjustable digital reference voltage from the second digital pulse width modulator, and to output the adjustable analog reference voltage.

15. A power system according to claim 11, further comprising a voltage divider connected between the output voltage and ground and including a first resistor and a second resistor;

wherein

the error amplifier is connected to the output voltage through a node between the first resistor and the second resistor.

16. A power system comprising:

a module arranged to provide an output voltage; and

a control circuit connected to the module including;

a fixed reference voltage circuit arranged to provide a fixed analog reference voltage;

a manually-adjustable reference voltage circuit arranged to convert an adjustable digital reference voltage to an adjustable analog reference voltage; and

an error amplifier arranged to compare the fixed analog reference voltage and a combination of the output voltage and the adjustable analog reference voltage and to provide a control signal to the module based upon the comparison of the fixed analog reference voltage and the combination of the output voltage and the adjustable analog reference voltage;

wherein the control circuit and the module are arranged such that;

an increase in the adjustable digital reference voltage causes a corresponding decrease in the output voltage; and

a decrease in the adjustable digital reference voltage causes a corresponding increase in the output voltage.

17. A power system according to claim 16, further comprising:

a first push-button connected to the manually-adjustable reference voltage circuit that, when manually activated, increases the adjustable digital reference voltage; and

a second push-button connected to the manually-adjustable reference voltage circuit that, when manually activated, decreases the adjustable digital reference voltage.

18. A power system according to claim 16, wherein the manually-adjustable reference voltage circuit includes:

a microcontroller including;

a non-volatile memory arranged to store a value corresponding to the adjustable digital reference voltage; and

a digital pulse width modulator arranged to output the adjustable digital reference voltage; and

a low-pass filter arranged to receive the adjustable digital reference voltage from the digital pulse width modulator and arranged to output the adjustable analog reference voltage.

19. A power system according to claim 16, wherein the adjustable digital reference voltage includes a coarse adjustable digital reference voltage and a fine adjustable fine digital reference voltage;

the manually-adjustable reference voltage circuit includes;

a microcontroller including;

a non-volatile memory arranged to store a value corresponding to the adjustable digital reference voltage;

a first digital pulse width modulator arranged to output the coarse adjustable digital reference voltage; and

a second digital pulse width modulator arranged to output the fine adjustable digital reference voltage; and

a low-pass filter is arranged to receive the coarse adjustable digital reference voltage from the first digital pulse width modulator, to receive the fine adjustable digital reference voltage from the second digital pulse width modulator, and to output the adjustable analog reference voltage.

20. A power system according to claim 16, further comprising:

a voltage divider connected between the output voltage and ground and including a first resistor and a second resistor; and

a third resistor connected to a node between the first resistor and the second resistor and connected to the adjustable analog reference voltage;

wherein

the error amplifier is connected to the output voltage through the node between the first resistor and the second resistor.