DC/DC boost converter with pulse skipping circuitry

• US 7,528,590 B2
• Filed: 10/01/2007
• Issued: 05/05/2009
• Est. Priority Date: 10/01/2007
• Status: Active Grant

• Current Assignee: Silicon Laboratories Incorporated
• Original Assignee: Silicon Laboratories Incorporated
• Inventors: Wei, Dazhi
• Primary Examiner(s): HAN, YOUNGHUIE JESSICA
• Application Number:
  US11/865,659
• Publication Number:
  US 20090085535A1
• Time in Patent Office: 582 Days
• Field of Search: 323/271, 323/282, 323/283, 323/284, 323/285, 323/288, 323/351
• US Class Current: 323/282
• CPC Class Codes: H02M 1/0032 Control circuits allowing low power mode operation, e.g. in standby mode
• CPC Class Codes: H02M 3/156 with automatic control of output voltage or current, e.g. switching regulators
• CPC Class Codes: Y02B 70/10 Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes

Abstract

A DC to DC boost converter circuit receives a DC input voltage and converts it to a DC output voltage at a different voltage level than the DC input voltage. The DC to DC boost converter includes a switching power converter for receiving the input voltage on an input and converting the input voltage to an output as the DC output voltage in response to pulse control signals. A switching controller generates the pulse control signals during a switching cycle. The switching controller further includes pulse skipping circuitry for generating a pulse width modulated signal to the switching power converter. A pulse width of the pulse width modulated signal is decreased responsive to a voltage level of an output voltage of the DC to DC boost converter being less than a control saw tooth waveform and the pulses width of the pulse width modulated signal is increased responsive to the voltage level of the output voltage of the DC to DC boost converter being greater than the control saw tooth waveform.

Claims

1. A DC to DC boost converter circuit for receiving a DC input voltage and converting it to a DC output voltage at a different voltage level than the DC input voltage, comprising:

a switching power converter for receiving the input voltage on an input and converting the input voltage to an output as the DC output voltage in response to pulse control signals;

a switching controller for generating the pulse control signals during a switching cycle; and

wherein the switching controller further includes pulse skipping circuitry for generating a pulse width modulated signal to the switching power converter, wherein a pulse width of the pulse width modulated signal is decreased responsive to a voltage level of an output voltage of the DC to DC boost converter being less than a control saw tooth waveform and the pulses width of the pulse width modulated signal is increased responsive to the voltage level of the output voltage of the DC to DC boost converter being greater than the control saw tooth waveform.

2. The DC to DC boost converter of claim 1, wherein the pulse skipping circuitry further comprises:

a comparator for comparing a voltage control signal associated with the output voltage of the DC to DC boost converter with a control signal associated with the control saw tooth waveform and generating an output signal responsive thereto; and

an SR latch having a first input connected to receive the output signal from the comparator and a second input connected to receive a reset signal, wherein the SR latch generates the pulse width modulated signal responsive to the voltage control signal and the reset signal.

3. The DC to DC boost converter of claim 2, wherein the pulse skipping circuitry further comprises circuitry for applying the control signal to an input of the comparator, the circuitry further comprises:

a transistor connected between the input of the comparator and ground, a gate of the transistor connected to receive the saw tooth waveform;

a current source connected to the input of the comparator; and

a capacitor connected between the input of the comparator and ground.

4. The DC to DC boost converter of claim 1, wherein the switching power converter further comprises:

an inductor connected to receive the DC input voltage;

a load capacitor connected to a regulated voltage output node;

a zero volt turn-on rectifier connected between the inductor and the output voltage node, wherein the zero volt turn-on rectifier further includes a first transistor associated with the first mode of operation and a second transistor associated with the second mode of operation, the first and second transistors selected responsive to control signals provided by the switching controller;

a plurality of transistor switches connected in parallel between an input of the zero volt turn-on rectifier and ground, wherein a first transistor switch of the plurality of transistor switches is a associated with the first mode of operation and a second transistor of the plurality of transistor switches is associated with the second mode of operation, the first and second transistor switches selected responsive to the control signals provided by the switching controller; and

switching control circuitry for controlling at least one transistor switch of the plurality of transistor switches responsive to the regulated voltage.

5. A DC to DC boost converter circuit for receiving a DC input voltage and converting it to a DC output voltage at a different voltage level than the DC input voltage, comprising:

a switching power converter for receiving the input voltage on an input and converting the input voltage to an output as the DC output voltage in response to pulse control signals, wherein the switching power converter further comprises;

an inductor connected to receive the DC input voltage;

a load capacitor connected to a regulated voltage output node;

a zero volt turn-on rectifier connected between the inductor and the output voltage node, wherein the zero volt turn-on rectifier further includes a first transistor associated with the first mode of operation and a second transistor associated with the second mode of operation, the first and second transistors selected responsive to control signals provided by the switching controller;

a plurality of transistor switches connected in parallel between an input of the zero volt turn-on rectifier and ground, wherein a first transistor switch of the plurality of transistor switches is a associated with the first mode of operation and a second transistor of the plurality of transistor switches is associated with the second mode of operation, the first and second transistor switches selected responsive to the control signals provided by the switching controller; and

a switching controller for controlling at least one transistor switch of the plurality of transistor switches responsive to the regulated voltage, wherein the switching controller further includes pulse skipping circuitry for generating a pulse width modulated signal to the switching power converter, wherein a pulse width of the pulse width modulated signal is decreased responsive to a voltage level of an output voltage of the DC to DC boost converter being less than a control saw tooth waveform and the pulses width of the pulse width modulated signal is increased responsive to the voltage level of the output voltage of the DC to DC boost converter being greater than the control saw tooth waveform.

6. The DC to DC boost converter of claim 5, wherein the pulse skipping circuitry further comprises:

a comparator for comparing a voltage control signal associated with the output voltage of the DC to DC boost converter with a control signal associated with the control saw tooth waveform and generating an output signal responsive thereto; and

an SR latch having a first input connected to receive the output signal from the comparator and a second input connected to receive a reset signal, wherein the SR latch generates the pulse width modulated signal responsive to the voltage control signal and the reset signal.

7. The DC to DC boost converter of claim 5, wherein the pulse skipping circuitry further comprises circuitry for applying the control signal to an input of the comparator, the circuitry further comprises:

a transistor connected between the input of the comparator and ground, a gate of the transistor connected to receive the saw tooth waveform;

a current source connected to the input of the comparator; and

a capacitor connected between the input of the comparator and ground.

8. A DC to DC boost converter circuit for receiving a DC input voltage and converting it to a DC output voltage at a different voltage level than the DC input voltage, comprising:

a switching power converter for receiving the input voltage on an input and converting the input voltage to an output as the DC output voltage in response to pulse control signals;

a switching controller for generating the pulse control signals during a switching cycle; and

wherein the switching controller further includes pulse skipping circuitry for generating a pulse width modulated signal to the switching power converter, wherein a pulse width of the pulse width modulated signal is decreased responsive to a voltage level of an output voltage of the DC to DC boost converter being less than a control saw tooth waveform and the pulses width of the pulse width modulated signal is increased responsive to the voltage level of the output voltage of the DC to DC boost converter being greater than the control saw tooth waveform, wherein the pulse skipping circuitry further comprises;

a comparator for comparing a voltage control signal associated with the output voltage of the DC to DC boost converter with a control signal associated with the control saw tooth waveform and generating an output signal responsive thereto;

an SR latch having a first input connected to receive the output signal from the comparator and a second input connected to receive a reset signal, wherein the SR latch generates the pulse width modulated signal responsive to the voltage control signal and the reset signal; and

circuitry for applying the control signal to an input of the comparator, the circuitry further comprises;

a transistor connected between the input of the comparator and ground, a gate of the transistor connected to receive the saw tooth waveform; and

a current source connected to the input of the comparator; and

a capacitor connected between the input of the comparator and ground.