Abstract: A multi-phase PFC (power factor correction) system, controller for the multi-phase PFC system and method of controlling the multi-phase PFC system are described. The controller includes a digital circuitry configured to calculate a delay value based on a positive current slope and a negative current slope for a first phase of the plurality of phases which is enabled for all load current conditions. In response to an increase in an average current reference, the digital circuitry is configured to enable a second phase of the plurality of phases such that a current output by the second phase is out of phase with a current output by the first phase by an amount corresponding to the delay value as referenced to a beginning of a boost charging portion of a switching cycle for the first phase.

Abstract: A power supply includes a primary winding, a secondary winding, a switch, and a controller. The secondary winding is magnetically coupled to the primary winding. The switch is coupled to the secondary winding and controls a state of current through the secondary winding. The controller controls the state of the switch based on an integrator voltage derived from monitoring a voltage from the secondary winding. For example, the controller activates the switch to an ON state in response to detecting a condition in which the magnitude of the monitored voltage of the secondary winding crosses a threshold value such as a magnitude of an output voltage produced from the secondary winding.

Abstract: A multi-phase PFC (power factor correction) system, controller for the multi-phase PFC system and method of controlling the multi-phase PFC system are described. The controller includes a digital circuitry configured to calculate a delay value based on a positive current slope and a negative current slope for a first phase of the plurality of phases which is enabled for all load current conditions. In response to an increase in an average current reference, the digital circuitry is configured to enable a second phase of the plurality of phases such that a current output by the second phase is out of phase with a current output by the first phase by an amount corresponding to the delay value as referenced to a beginning of a boost charging portion of a switching cycle for the first phase.

Abstract: Techniques to send digital information from the secondary side to the primary side of a power converter, such as a flyback power converter, without the need for a separate, isolated communication channel. The power converter of this disclosure may send digital information from secondary side to the primary side through a power transformer while the power converter operates in a mixed mode scenario, e.g. critical conduction mode (CRCM) and discontinuous conduction mode (DCM). In CRCM, a controller circuit for the power converter may encode digital information by modulating the diode conduction time in a switching cycle. In DCM, the controller circuit may encode digital information by modulating the period of time for each switching cycle, e.g. increased period, decreased period or no change to the period.

Abstract: A synchronous rectifier includes: an integrator configured to integrate a voltage across a secondary side winding of a transformer over an integral period having an expected zero integral value; a first comparator configured to detect an end of a demagnetization phase of the secondary side winding based on diode detection; and a digital circuit configured to adjust a channel gain of the synchronous rectifier based on an integration error at the end of the integral period, the integration error corresponding to the difference between the integrated voltage at the end of the integral period and the expected zero integral. Corresponding methods of gain tuning and a power converter are also described.

Abstract: Techniques to send digital information from the secondary side to the primary side of a power converter, such as a flyback power converter, without the need for a separate, isolated communication channel. The power converter of this disclosure may send digital information from secondary side to the primary side through a power transformer while the power converter operates in a mixed mode scenario, e.g. critical conduction mode (CRCM) and discontinuous conduction mode (DCM). In CRCM, a controller circuit for the power converter may encode digital information by modulating the diode conduction time in a switching cycle. In DCM, the controller circuit may encode digital information by modulating the period of time for each switching cycle, e.g. increased period, decreased period or no change to the period.

Abstract: A synchronous rectifier includes: an integrator configured to integrate a voltage across a secondary side winding of a transformer over an integral period having an expected zero integral value; a first comparator configured to detect an end of a demagnetization phase of the secondary side winding based on diode detection; and a digital circuit configured to adjust a channel gain of the synchronous rectifier based on an integration error at the end of the integral period, the integration error corresponding to the difference between the integrated voltage at the end of the integral period and the expected zero integral. Corresponding methods of gain tuning and a power converter are also described.

Abstract: A power supply includes a primary winding, a secondary winding, a switch, and a controller. The secondary winding is magnetically coupled to the primary winding. The switch is coupled to the secondary winding and controls a state of current through the secondary winding. The controller controls the state of the switch based on an integrator voltage derived from monitoring a voltage from the secondary winding. For example, the controller activates the switch to an ON state in response to detecting a condition in which the magnitude of the monitored voltage of the secondary winding crosses a threshold value such as a magnitude of an output voltage produced from the secondary winding.

Abstract: In accordance with an embodiment, a method of measuring a gas concentration includes modulating an infrared light source according to a frequency-hopped sequence or according to a pulse sequence, receiving a microphone signal from an output of a microphone acoustically coupled to a gas exposed to infrared light produced by the infrared light source; bandpass filtering the microphone signal using a bandpass filter; and estimating the gas concentration from the filtered microphone signal.

Abstract: A power converter, such as a flyback power converter, configured to send digital information from a secondary side to a primary side of the power converter and notify the secondary side that the communication has been received by the primary side. In this manner the secondary side may receive an acknowledgement (ACK) from the primary side, while maintaining isolation between the primary side and secondary side. To implement the ACK response to digital communication from the secondary side, the primary side may delay generating a PWM pulse to the primary side switch. The secondary side may detect the missing PWM pulse based on a change in the integrated secondary side current and determine that the primary side has sent an ACK response.

Abstract: A high-speed, low-latency configurable digital interface for a voltage regulator includes a first hardwired unit, a second hardwired unit and a programmable microcontroller interfaced between the first and second hardwired units. The first hardwired unit is operable to deserialize incoming frames received over the configurable digital interface into commands and data associated with operation of a switching voltage regulator, and serialize outgoing data into new frames for transmission over the configurable digital interface. The second hardwired unit is operable to process the commands included in the incoming frames deserialized by the first hardwired unit, and provide the outgoing data to be serialized into new frames by the first hardwired unit. The programmable microcontroller is operable to change one or more of the commands and data flowing between the first and second hardwired units.

Abstract: The disclosure describes techniques to send digital information from the secondary side to the primary side of a power converter, such as a flyback power converter, and notify the secondary side that the communication has been received by the primary side. In this manner the secondary side may receive an acknowledgement (ACK) from the primary side, while maintaining isolation between the primary side and secondary side. To implement the ACK response to digital communication from the secondary side, the primary side may delay generating a PWM pulse to the primary side switch. The secondary side may detect the missing PWM pulse based on a change in the integrated secondary side current and determine that the primary side has sent an ACK response.

Abstract: In accordance with an embodiment, a method of measuring a gas concentration includes modulating an infrared light source according to a frequency-hopped sequence or according to a pulse sequence, receiving a microphone signal from an output of a microphone acoustically coupled to a gas exposed to infrared light produced by the infrared light source; bandpass filtering the microphone signal using a bandpass filter; and estimating the gas concentration from the filtered microphone signal.

Abstract: In accordance with an embodiment, a method of measuring a gas concentration includes modulating an infrared light source according to a frequency-hopped sequence or according to a pulse sequence, receiving a microphone signal from an output of a microphone acoustically coupled to a gas exposed to infrared light produced by the infrared light source; bandpass filtering the microphone signal using a bandpass filter; and estimating the gas concentration from the filtered microphone signal.

Abstract: The disclosure describes techniques to send digital information from the secondary side to the primary side of a power converter, such as a flyback power converter. By modulating the amount of time between zero voltage switching (ZVS) pulses initiated by a synchronous rectification (SR) transistor on the secondary side, a power converter circuit of this disclosure may communicate digital information to the primary side from the secondary side. The power converter circuit of this disclosure may include stable, accurate and reliable ZVS pulse detection techniques on the primary side to determine slight changes in the period between ZVS pulses from the secondary side. A controller circuit on the secondary side may encode digital information by modulating the ZVS period, e.g. increased period, decreased period or no change to the period.

Abstract: A system and method to identify whether a removable battery pack inserted into a battery-powered device is an authorized battery pack for the device. Battery-powered devices may include a battery-powered drill, saw, flashlight or other type of device. The battery-powered device may send an authentication query to the battery pack. If the battery-powered device does not receive a valid reply from the battery pack, the battery-powered device may verify that the battery-powered device is still within a phase-out period that allows the battery-powered device to use a battery pack with an invalid authentication. If the phase-out period has expired, the battery-powered device may disable the use of the battery pack with an invalid authentication. If the phase-out period is still running, the battery-powered device may allow the use of the battery pack with an invalid authentication, but only for a limited number of battery pack recharge cycles.

Abstract: A controller for a switching mode power converter is configured to drive a switching element to selectively connect a supply to a primary side winding of a transformer to generate a regulated voltage, current, or power at a secondary side winding of the transformer. The controller is configured to, for each switching cycle, select a peak current value from a plurality of peak current values calculated to drive an oscillating voltage at the switching element to correspond to a voltage valley and in response to determining a voltage valley is occurring at the oscillating voltage at the switching element, output an enabling signal to cause the switching element to generate a channel electrically connecting the supply to the primary side winding until current at the switching element is not less than the selected peak current value.

Abstract: In accordance with an embodiment, a method of measuring a gas concentration includes modulating an infrared light source according to a frequency-hopped sequence or according to a pulse sequence, receiving a microphone signal from an output of a microphone acoustically coupled to a gas exposed to infrared light produced by the infrared light source; bandpass filtering the microphone signal using a bandpass filter; and estimating the gas concentration from the filtered microphone signal.

Abstract: A high-speed, low-latency configurable digital interface for a voltage regulator includes a first hardwired unit, a second hardwired unit and a programmable microcontroller interfaced between the first and second hardwired units. The first hardwired unit is operable to deserialize incoming frames received over the configurable digital interface into commands and data associated with operation of a switching voltage regulator, and serialize outgoing data into new frames for transmission over the configurable digital interface. The second hardwired unit is operable to process the commands included in the incoming frames deserialized by the first hardwired unit, and provide the outgoing data to be serialized into new frames by the first hardwired unit. The programmable microcontroller is operable to change one or more of the commands and data flowing between the first and second hardwired units.

Abstract: A system and method to identify whether a removable battery pack inserted into a battery-powered device is an authorized battery pack for the device. Battery-powered devices may include a battery-powered drill, saw, flashlight or other type of device. The battery-powered device may send an authentication query to the battery pack. If the battery-powered device does not receive a valid reply from the battery pack, the battery-powered device may verify that the battery-powered device is still within a phase-out period that allows the battery-powered device to use a battery pack with an invalid authentication. If the phase-out period has expired, the battery-powered device may disable the use of the battery pack with an invalid authentication. If the phase-out period is still running, the battery-powered device may allow the use of the battery pack with an invalid authentication, but only for a limited number of battery pack recharge cycles.