Method and system of slow output voltage ramp control for a power supply
AssigneeADC DCL Systems, Inc.
InventorsCharles Weston Lomax, Jr., Christopher Tad Ammann
Life of this patent
Estimating the term…
Abstract
A pulse width modulation controller is coupled to a feedback voltage that is proportional to the power supply output voltage. The controller adjusts a current sense threshold in the controller in response to the feedback voltage. An offset voltage is generated for a predetermined time after the power-up of the power supply. A sum of the offset voltage and a primary current sense node voltage is applied to a current sense input of the controller. The controller generates a switch control signal in response to the sum voltage being less than the current sense threshold. The duty cycle of an output control switch is changed by the switch control signal thus adjusting the output voltage ramp.
Claims22
A power supply with output voltage ramp control, the power supply comprising:
- a controller having a current sense input, a voltage feedback input, and a control output, the voltage feedback input coupled to a feedback voltage that is proportional to the output voltage, the controller adjusting a current sense threshold in response to the feedback voltage;
- a control circuit apparatus coupled to the current sense input of the controller, the control circuit apparatus comprising:
- an offset voltage generator that generates an offset voltage during a predetermined time interval;
- and
- a timer controlled switch coupled to the offset voltage generator, the timer controlled switch having a capability for applying a sum voltage of the offset voltage and a node voltage, from a primary current sense node, to the current sense input such that the control output of the controller is on during the predetermined time interval;
- and
- an output control switch, coupled to the control output, that turns on when the control output is on.
In a power supply, an apparatus for controlling the slope of an output voltage, the apparatus comprising:
- a feedback voltage coupled to the output voltage, the feedback voltage being proportional to the output voltage;
- an oscillator that generates an oscillator signal having a predetermined frequency;
- a pulse width modulating controller having a current sense input, a voltage feedback input, an oscillator input, and a control output, the voltage feedback input coupled to the feedback voltage, the controller adjusting a current sense threshold in response to the feedback voltage, the oscillator input coupled to the oscillator signal;
- a primary current sense node having a predetermined node voltage;
- a control circuit apparatus coupled to the current sense input of the controller, the control circuit apparatus comprising:
- an offset voltage generator comprising a current sense resistor that generates an offset voltage during a predetermined time interval;
- and
- a timer controlled switch coupled to the offset voltage generator, the timer controlled switch having a capability for applying a sum voltage of the offset voltage and the node voltage to the current sense input such that the control output of the controller is on during the predetermined time interval;
- and
- an output control switch, coupled to the control output, that turns on and off at a frequency that is substantially equal to the predetermined frequency and the control output sets a time period that the output control switch is on.
A method for controlling an output voltage ramp in a power supply, the method comprising:
- coupling to a controller a feedback voltage that is proportional to the power supply output voltage;
- adjusting a current sense threshold in the controller in response to the feedback voltage;
- applying a sum voltage of an offset voltage and a node voltage to a current sense input of the controller;
- the controller generating a switch control signal, the switch control signal indicating an on condition in response to the sum voltage being less than the current sense threshold;
- and
- an output control switch adjusting the output voltage ramp in response to the switch control signal.
A power supply having an output voltage ramp-up with multiple, controllable slopes, the power supply comprising:
- a feedback voltage coupled to the output voltage of the power supply, the feedback voltage being proportional to the output voltage;
- a controller having a current sense input, a voltage feedback input, a reference voltage, and a control output, the voltage feedback input coupled to the feedback voltage, the controller adjusting a current sense threshold in response to the feedback voltage;
- a primary current sense node having a predetermined node voltage;
- a control circuit apparatus coupled to the current sense input of the controller, the control circuit apparatus comprising:
- an offset voltage generator comprising a current sense resistor that generates an offset voltage during a predetermined time interval;
- and
- a timer that generates a switch shut-off voltage after the predetermined time interval, the predetermined time interval being less than a time for the reference voltage to reach a level that is substantially similar to the output voltage;
- and
- a timer controlled switch coupled to the offset voltage generator and the timer, the timer controlled switch having a capability for applying a sum of the offset voltage and the node voltage to the current sense input such that the control output of the controller is on during the predetermined time interval;
- and
- an output control switch, coupled to the control output, that turns on when the control output is on.
A power supply with output voltage ramp control, the power supply comprising:
- a control circuit apparatus for generating an offset voltage for a predetermined time interval;
- a controller for generating an output control signal, the controller coupled to a primary current sense node and the control circuit apparatus, the controller adjusting a current sense threshold in response to a feedback voltage, that is proportional to the output voltage, and a sum of a primary current sense node voltage and the offset voltage;
- and
- an output control switch, coupled to the controller, that turns on in response to the output control signal to control the output voltage.
A method for controlling an output voltage ramp in a power supply, the method comprising:
- coupling a feedback voltage that is proportional to the power supply output voltage;
- adjusting a current sense threshold in response to the feedback voltage;
- creating a sum voltage from an offset voltage and a current sense node voltage;
- generating a switch control signal, the switch control signal indicating an on condition in response to the sum voltage being less than the current sense threshold;
- and
- adjusting the output voltage ramp in response to the switch control signal.
Dependencies are inferred from the claim text.