Method and apparatus for sensing multiple voltage values from a single terminal of a power converter controller
An example controller for a power converter includes a switching control coupled to switch a power switch of the power converter to control a transfer of energy from an input of the power converter to an output of the power converter. A sensor is coupled to sample a single terminal of the controller during a portion of an off time of the power switch to output a signal representative of an output voltage of the power converter. The sensor is further coupled to sample the single terminal during a portion of an on time of the power switch to output a signal representative of a line input voltage of the power converter. The switching control is responsive to the sensor.
1. A controller for a power converter, comprising:
a switching control coupled to switch a power switch of the power converter to control a transfer of energy from an input of the power converter to an output of the power converter; and
a sensor coupled to sample a single terminal of the controller during a portion of an off time of the power switch to output a signal representative of an output voltage of the power converter, the sensor further coupled to sample the single terminal during a portion of an on time of the power switch to output a signal representative of a line input voltage of the power converter, wherein the switching control is responsive to the sensor.
2. The controller of claim 1 wherein the sensor is coupled to sample the single terminal during the portion of the off time of the power switch after a first delay after the power switch transitions from an on state to an off state.
3. The controller of claim 1 wherein the sensor is coupled to sample the single terminal during the portion of the on time of the power switch after a second delay after the power switch transitions from an off state to an on state.
4. The controller of claim 1 wherein the sensor is coupled to sample a voltage representative of the output voltage of the power converter during the portion of the off time of the power switch.
5. The controller of claim 1 wherein the sensor is coupled to sample a current representative of the line input voltage of the power converter during the portion of the on time of the power switch.
6. The controller of claim 1 wherein the controller is comprised in an integrated circuit controller for the power converter.
7. The controller of claim 6 wherein the integrated circuit controller for the power converter further comprises the power switch.
8. The controller of claim 1 wherein the switching control is coupled to switch the power switch of the power converter to regulate the output of the power converter in response to the sensor.
9. The controller of claim 1 wherein the sensor includes a capacitor coupled to be charged to a sample voltage during the portion of the off time of the power switch, wherein the sample voltage is representative of a voltage of the single terminal during the portion of the off time of the power switch.
10. The controller of claim 9 wherein the sensor further comprises a buffer circuit coupled between the single terminal and the capacitor to mirror the voltage at the single terminal to the capacitor.
11. The controller of claim 1 further comprising a power limiter coupled between the sensor and the switching control, wherein the power limiter is coupled to output a power limit signal to the switching control to limit an input power of the power converter in response to the signal representative of the line input voltage of the power converter.
12. The controller of claim 1 further comprising a line under voltage detector coupled between the sensor and the switching control, wherein the line under voltage detector coupled to output a line under voltage signal to the switching control in response to the signal representative of the line input voltage of the power converter and a line voltage threshold.
13. The controller of claim 1 further comprising an auto restart detector coupled between the sensor and the switching control, wherein the auto restart detector is coupled to output an auto restart signal to the switching control to indicate to the switching control to enter an auto restart mode, wherein the auto restart signal is responsive to the signal representative of the output voltage of the power converter.