Abstract: An error amplifier includes an output pin coupled to a pulse width modulation (PWM) comparator of a buck-boost converter. A first transconductance amplifier adjusts an output current at the output pin and operates in a constant voltage mode. The first transconductance amplifier includes a first positive input to receive a first voltage reference and a first negative input coupled to a tap point of a voltage divider coupled between a voltage bus and a ground of the buck-boost converter. A second transconductance amplifier also adjusts the output current at the output pin and operates in a constant current mode. The second transconductance amplifier includes a second positive input to receive a second voltage reference and a second negative input coupled to a current sense amplifier, the current sense amplifier being coupled to a sense resistor positioned inline along the voltage bus.

Abstract: A method comprising controlling operation, by a secondary-side controlled Universal Serial Bus Power Delivery (USB-PD) alternating current to direct current (AC-DC) converter, a low-side field-effect transistor (FET). In response to controlling operation of the low-side FET, the method further includes triggering a zero-cross detection circuit. The method further includes measuring a first period of time between controlling operation of the low-side FET and triggering the zero-cross detection circuit. The method further includes measuring a second period of time between controlling operation of a high-side FET and triggering the zero-cross detection circuit. The method further includes adjusting a third period of time based on the first period of time and the second period of time, wherein the third period of time corresponds to a dead time between controlling operation of the high-side FET and the low-side FET.

Abstract: Disclosed are techniques for using a sense amplifier for the voltage path having an adjustable gain and a current amplifier for the current path having an adjustable sample-hold interval for demodulation of in-band ASK data in power transmitting devices of a wireless charging system. The sample-hold interval may be adjusted as a function of the error rate of the demodulated data and used to sample the modulated current when the adjustable gain of the voltage path is not able to track the modulated voltage. The adjustable sample-hold may function as a variable reference of a comparator used to compare the sampled current to generate the sensed current. A controller may flexibly adjust the gain, adjust the sample-hold interval, and/or select the sensed voltage or the sensed current path for further filtering, demodulation, decoding, and processing depending on the error rate under various loading, coupling scenarios, and phases of power transfer.

Abstract: A secondary side controller for a flyback converter includes an integrated circuit (IC), which in turn includes: a synchronous rectifier (SR) sense pin coupled to a drain of an SR transistor on a secondary side of the flyback converter; a capacitor having a first side coupled to the SR sense pin, the capacitor to charge or discharge responsive to a voltage sensed at the SR sense pin; a diode-connected transistor coupled between a second side of the capacitor and ground; a first current mirror coupled to the diode-connected transistor and configured to receive, as input current, a reference current from a variable current source; and a peak detect transistor coupled to the diode-connected transistor and to an output of the first current mirror. The peak detect transistor is to output a peak detection signal in response to detecting current from the capacitor drop below the reference current.

Abstract: A system includes a first USB Type-C Power Delivery (USB-C/PD) port and a control circuit operatively coupled to the first USB-C/PD port. The control circuit is configured to determine whether a short circuit condition has occurred based on a first threshold voltage. The control circuit is also configured to turn off a ground isolation switch when short circuit condition occurs. The control circuit is further configured to determine a whether a voltage on a ground line is less than a second threshold voltage. The control circuit is further configured to turn on the ground isolation switch when the voltage on the ground line is less than the second threshold voltage. The control circuit may perform one or more error recovery operations after turning on the ground isolation switch.

Abstract: Controlling power factor correction (PFC) in a secondary-controlled alternating current (AC) to direct current (DC) (AC-DC) power adapter is described. In one embodiment, an apparatus includes a transformer, a primary-side controller coupled to the transformer, a PFC component coupled to the primary-side controller, and a secondary-side controller coupled to the transformer. The secondary-side controller is configured at least to obtain data informative of an amount of power, and control, based on the amount of power, a PFC operating mode of the PFC component.

Abstract: A primary-side-controlled fly-back converter is provided to eliminate cross-conduction between a power-switch (PS) on a primary side and a synchronous-rectifier (SR) on a secondary side when operating in continuous conduction mode (CCM). Generally, the converter includes a transformer having a primary coupled to a rectified AC input through the PS, and a secondary coupled to a DC output through the SR, the SR having a drain coupled to the secondary winding. A fly-back-controller includes a primary-controller operable to control a duty cycle of the PS, and a secondary-controller operable to turn OFF the SR when the PS turns ON in CCM. The secondary-controller includes a CCM zero-crossing-detector comparator having a first input coupled to the drain of the SR through a capacitor, and is operable to detect a sharp change in a drain voltage when the PS turns ON during CCM, and to output a signal to turn OFF the SR.

Abstract: Controlling an active clamp field effect transistor (FET) and a primary-side FET in a secondary-controlled active clamp converter is described. In one embodiment, an apparatus includes a primary-side FET coupled to a transformer and an active clamp FET disposed on a primary side of the transformer. A secondary-side controller is configured to control the active clamp FET and the primary-side FET across a same galvanic isolation barrier.

Abstract: A secondary side controller for a flyback converter can include a synchronous rectifier (SR) gate driver pin coupled to a gate of an SR transistor on a secondary side of the flyback converter. An error amplifier is coupled to an output of a voltage bus of the flyback converter, the error amplifier to generate an error signal indicative of a voltage of the output of the voltage bus. Control logic is coupled to the error amplifier and to the SR transistor, the control logic to: detect when the voltage is at least a threshold percentage higher than a sink voltage required by a sink device coupled to the output of the voltage bus; detect assertion of a skip mode signal; and cause the SR transistor to be driven during a skip mode such as to partially discharge an output capacitor coupled to the output of the voltage bus.

Abstract: A system includes a first USB Type-C Power Delivery (USB-C/PD) port and a control circuit operatively coupled to the first USB-C/PD port. The control circuit is configured to determine whether a short circuit condition has occurred based on a first threshold voltage. The control circuit is also configured to turn off a ground isolation switch when short circuit condition occurs. The control circuit is further configured to determine a whether a voltage on a ground line is less than a second threshold voltage. The control circuit is further configured to turn on the ground isolation switch when the voltage on the ground line is less than the second threshold voltage. The control circuit may perform one or more error recovery operations after turning on the ground isolation switch.

Abstract: Universal Serial Bus Type-C (USB-C) controllers with a floating gate driver with programmable drive strength for a wide range of USB power delivery applications in electronic devices described. A USB-C controller includes a floating gate driver and control logic. The floating gate driver includes p-channel field-effect transistors (FETs) coupled in parallel between a first terminal and a second terminal and p-channel pre-gate drivers. Each p-channel pre-gate driver is coupled to a gate of one of the p-channel FETs. The floating gate driver includes n-channel FETs coupled in parallel between the second terminal and a third terminal and n-channel pre-gate drivers, each n-channel pre-gate driver being coupled to a gate of one of the plurality of n-channel FETs. The control logic sends one or more control signals to activate a first number of p-channel pre-gate drivers and a second number of n-channel pre-gate drivers based on an output voltage.

Abstract: A mode-transition architecture for USB controllers is described herein. In an example embodiment, an integrated circuit (IC) controller includes a controller coupled to a slope compensation circuit, the controller to detect a transition of a buck-boost converter from a first mode having a first duty cycle to a second mode having a second duty cycle that is less or more than the first duty cycle. The controller controls the slope compensation circuit to nullify an error in an output caused by the transition. The controller can cause the slope compensation circuit to apply a charge stored in a capacitor during a first cycle to start a second cycle with a higher voltage than the first cycle.

Abstract: Communicating fault conditions between primary-side and secondary-side controllers of a Universal Serial Bus Power Delivery (USB-PD) device is described. The primary-side controller receives a control signal from the secondary-side controller across a galvanic isolation barrier. The primary-side controller converts the control signal into a first pulse signal and applies the first pulse signal to control a primary-side switch. When the primary-side controller detects that a first fault condition has occurred, the primary-side controller communicates a first information signal about the first fault condition to the secondary-side controller across the galvanic isolation barrier. The first information signal is generated by converting the control signal into a second pulse signal having a different pulse width than the first pulse signal. The primary-side controller applies the second pulse signal to control the primary-side power switch.

Abstract: Disclosed are techniques for using a sense amplifier for the voltage path having an adjustable gain and a current amplifier for the current path having an adjustable sample-hold interval for demodulation of in-band ASK data in power transmitting devices of a wireless charging system. The sample-hold interval may be adjusted as a function of the error rate of the demodulated data and used to sample the modulated current when the adjustable gain of the voltage path is not able to track the modulated voltage. The adjustable sample-hold may function as a variable reference of a comparator used to compare the sampled current to generate the sensed current. A controller may flexibly adjust the gain, adjust the sample-hold interval, and/or select the sensed voltage or the sensed current path for further filtering, demodulation, decoding, and processing depending on the error rate under various loading, coupling scenarios, and phases of power transfer.

Abstract: A gate driver circuit for a synchronous rectifier (SR) of a wireless power receiver (WPR) system includes: a first RC filter that outputs a delayed turn-on signal for a first high-side SR switch based on a signal input to the filter that indicates a zero-crossing condition for a coil current of the WPR system in a first direction; a second RC filter that outputs a delayed turn-on signal for a second high-side SR switch based on a signal input to the filter that indicates a zero-crossing condition for the coil current in the opposite direction; a first digital delay-and-hold circuit electrically connected to the output of the first RC filter and that stabilizes the delayed turn-on signal output by the first filter; and a second digital delay-and-hold circuit electrically connected to the output of the second RC filter and that stabilizes the delayed turn-on signal output by the second filter.

Abstract: A secondary side controller for a flyback converter includes an integrated circuit (IC), which in turn includes: a synchronous rectifier (SR) sense pin coupled to a drain of an SR transistor on a secondary side of the flyback converter; a capacitor having a first side coupled to the SR sense pin, the capacitor to charge or discharge responsive to a voltage sensed at the SR sense pin; a diode-connected transistor coupled between a second side of the capacitor and ground; a first current mirror coupled to the diode-connected transistor and configured to receive, as input current, a reference current from a variable current source; and a peak detect transistor coupled to the diode-connected transistor and to an output of the first current mirror. The peak detect transistor is to output a peak detection signal in response to detecting current from the capacitor drop below the reference current.

Abstract: A secondary-side-controller for a QR flyback converter and method for operating the same are provided. Generally, the secondary-side-controller includes a driver configured to control a power-switch (PS) on a primary side of converter to turn on the PS when a sinusoidal input voltage to the converter is at one of a plurality of valleys, an analog-to-digital-converter (ADC) to read the input voltage, output voltage, and load current, and generate digital signals based thereon. A valley-controller coupled to the driver, ADC, a look-up-table and a pulse width modulator (PWM) receives the signals from the ADC and using the look-up-table determines at which valley of the plurality of valleys to couple a PWM signal from the PWM to the driver. The valley-controller is operable for each switching cycle of the PS to increment, decrement or leave unchanged the valley at which the PWM signal is coupled from the PWM to the driver.

Abstract: An IC controller for USB Type-C device includes an error amplifier (EA), which includes an EA output coupled to a PWM comparator of a buck-boost converter; a first transconductance amplifier to adjust a current at the EA output, the first transconductance amplifier operating in a constant voltage mode; and a second transconductance amplifier to adjust the current at the EA output, the second transconductance amplifier operating in a constant current mode. A first set of programmable registers is to store a first set of increasingly higher transconductance values. A second set of programmable registers is to store a second set of increasingly higher transconductance values. Control logic is to: cause the first transconductance amplifier to operate while sequentially using transconductance values stored in the first set of programmable registers; and cause the second transconductance amplifier to operate while sequentially using transconductance values stored in the second set of programmable registers.

Abstract: A mode-transition architecture for USB controllers is described herein. In an example embodiment, an integrated circuit (IC) controller includes a controller coupled to a slope compensation circuit, the controller to detect a transition of a buck-boost converter from a first mode having a first duty cycle to a second mode having a second duty cycle that is less or more than the first duty cycle. The controller controls the slope compensation circuit to nullify an error in an output caused by the transition. The controller can cause the slope compensation circuit to apply a charge stored in a capacitor during a first cycle to start a second cycle with a higher voltage than the first cycle.

Abstract: A USB-power delivery integrated circuit controller includes: one or more driver circuits configured to control operation of a buck-boost converter; a regulator configured to regulate an internal supply voltage of the controller from a variable input voltage of the buck-boost converter in a regulation mode, and to pass the variable input voltage as the internal supply voltage without regulation in a bypass mode, the regulator being in the bypass mode when the variable input voltage is below the internal supply voltage, the regulator including an amplifier and a pass transistor configured to pass a current that is inversely proportional to an output of the amplifier; a clamping circuit configured to limit an overdrive voltage of the pass transistor during an inrush current event; and an override circuit configured to deactivate the clamping circuit in the bypass mode when the current passed by the pass transistor is below a current threshold.