Abstract: In described examples, an isolated DC-DC converter includes: an input node for receiving an input voltage; a transformer including a primary side having first and second terminals and a primary side ground; and first and second low-side switches. The first low-side switch is coupled between the first terminal and the primary side ground. The second low-side switch is coupled between the second terminal and the primary side ground. A first voltage is across the first low-side switch, and a second voltage is across the second low-side switch. Also, the isolated DC-DC converter includes first and second high-side switches. The first high-side switch is coupled between the first terminal and the input node and is configured to be activated by a voltage at the second terminal. The second high-side switch is coupled between the second terminal and the input node and is configured to be activated by a voltage at the first terminal.

Abstract: Disclosed examples include isolated load switch driver circuits to drive a load, including an impedance circuit that receives a digital input voltage signal from a signal source, and selectively allows a current signal to flow from the signal source to charge a buffer capacitor. An impedance control circuit controls the impedance circuit to limit the current signal in response to the buffer capacitor reaching a first threshold voltage, and an output circuit provides an output isolated from the digital input voltage signal to switch the load. A signaling circuit selectively enables the output circuit to draw power from the buffer capacitor in response to the voltage of the buffer capacitor reaching the first threshold voltage.

Abstract: Disclosed examples include isolated load switch driver circuits to drive a load, including an impedance circuit that receives a digital input voltage signal from a signal source, and selectively allows a current signal to flow from the signal source to charge a buffer capacitor. An impedance control circuit controls the impedance circuit to limit the current signal in response to the buffer capacitor reaching a first threshold voltage, and an output circuit provides an output isolated from the digital input voltage signal to switch the load. A signaling circuit selectively enables the output circuit to draw power from the buffer capacitor in response to the voltage of the buffer capacitor reaching the first threshold voltage.

Abstract: A transducer has an input and produces a mechanical output, wherein the magnitude of the mechanical output of the transducer is dependent on the frequency and magnitude of current at the input. A driver for the transducer includes a device having a transfer function associated with the device, the device having a device input and a device output, the device output being connectable to the input of the transducer and the device input being connectable to a power source. The device attenuates the current output at a frequency that causes a peak in the magnitude of the mechanical output of the transducer.

Abstract: Disclosed examples include isolated load switch driver circuits to drive a load, including an impedance circuit that receives a digital input voltage signal from a signal source, and selectively allows a current signal to flow from the signal source to charge a buffer capacitor. An impedance control circuit controls the impedance circuit to limit the current signal in response to the buffer capacitor reaching a first threshold voltage, and an output circuit provides an output isolated from the digital input voltage signal to switch the load. A signaling circuit selectively enables the output circuit to draw power from the buffer capacitor in response to the voltage of the buffer capacitor reaching the first threshold voltage.

Abstract: Disclosed examples include isolated phase shifted dual active bridge DC to DC converters with a first bridge circuit operative according to a primary side clock signal to provide a primary voltage signal to a transformer primary winding, a second bridge circuit operative according to a secondary side clock signal to convert a secondary voltage signal from a transformer secondary winding to provide an output voltage signal, and a secondary side control circuit that alternately operates in a first mode to regulate the output voltage signal by controlling a phase shift angle between switching transitions of secondary side switching control signals and switching transitions of the secondary side clock signal, and a second mode to discontinue the secondary side switching control signals and synchronize the secondary side clock signal to transitions in the secondary voltage signal while the secondary side switching control signals are discontinued.

Abstract: Disclosed examples include isolated load switch driver circuits to drive a load, including an impedance circuit that receives a digital input voltage signal from a signal source, and selectively allows a current signal to flow from the signal source to charge a buffer capacitor. An impedance control circuit controls the impedance circuit to limit the current signal in response to the buffer capacitor reaching a first threshold voltage, and an output circuit provides an output isolated from the digital input voltage signal to switch the load. A signaling circuit selectively enables the output circuit to draw power from the buffer capacitor in response to the voltage of the buffer capacitor reaching the first threshold voltage.

Abstract: An electronic device, which includes an H-bridge circuit and a miniaturized transformer that is coupled to operate at VHF frequency, and a driver circuit for an n-type power transistor of the H-bridge circuit are disclosed. The driver circuit includes a first p-type transistor and an n-type transistor coupled between an upper rail and a lower rail, with an output taken between the drains of the first p-type transistor and the n-type transistor being coupled to a gate of the n-type power transistor. The driver circuit also includes a sample-and-hold capacitor coupled to capture a drain voltage for the first n-type power transistor on a first edge of a control signal for the first n-type power transistor and a comparator coupled to compare the captured drain voltage to a lower rail on a given edge of a clock signal and to provide a comparator value.

Abstract: An electronic device, which includes an H-bridge circuit and a miniaturized transformer that is coupled to operate at VHF frequency, and a driver circuit for an n-type power transistor of the H-bridge circuit are disclosed. The driver circuit includes a first p-type transistor and an n-type transistor coupled between an upper rail and a lower rail, with an output taken between the drains of the first p-type transistor and the n-type transistor being coupled to a gate of the n-type power transistor. The driver circuit also includes a sample-and-hold capacitor coupled to capture a drain voltage for the first n-type power transistor on a first edge of a control signal for the first n-type power transistor and a comparator coupled to compare the captured drain voltage to a lower rail on a given edge of a clock signal and to provide a comparator value.

Abstract: Methods and systems for providing electrical power using an isolated DC-DC converter, including the actions of: a) providing current to a primary side of a transformer at multiple predetermined open loop current levels using a power supply, said power supply providing said open loop current levels in increasing amplitude order and at predetermined times, said open loop current levels and times being selected to ramp a voltage across output terminals connected to a secondary side of said transformer so that after said power supply provides a maximum one of said open loop current levels, said voltage reaches a threshold sufficient to enable a closed loop controller connected to said output terminals to send a feedback signal to said primary side, said threshold being insufficient to fully power said output terminals; and b) sending said feedback signal to said primary side using said closed loop controller when said voltage reaches said threshold, said power supply controlled in response to said feedback signal

Abstract: Described examples include DC to DC converters and systems with switching circuitry formed by four series-connected switches, inductors connected between the ends of the switching circuitry and corresponding output nodes, and with a flying capacitor coupled across interior switches of the switching circuitry and a second capacitor coupled across the ends of the switching circuitry. A control circuit operates the switching circuit to control a voltage signal across the output nodes using a first clock signal and a phase shifted second clock signal to reduce output ripple current and enhance converter efficiency using valley current control. The output inductors are wound on a common core in certain examples.

Abstract: Described examples include DC to DC converters and systems with switching circuitry formed by four series-connected switches, inductors connected between the ends of the switching circuitry and corresponding output nodes, and with a flying capacitor coupled across interior switches of the switching circuitry and a second capacitor coupled across the ends of the switching circuitry. A control circuit operates the switching circuit to control a voltage signal across the output nodes using a first clock signal and a phase shifted second clock signal to reduce output ripple current and enhance converter efficiency using valley current control. The output inductors are wound on a common core in certain examples.

Abstract: Disclosed examples include multiple output DC to DC converters with a buck converter including a half bridge switching circuit and transformer primary winding to provide a first output voltage signal, as well as a boost converter to provide an isolated second output voltage signal. The boost converter includes a transformer secondary winding magnetically coupled with the primary winding to provide a boost converter inductor, a switching circuit, an output diode providing the second output voltage signal, and a PWM controller that synchronizes the boost converter switching with the low side switch of the buck converter based on a sensed voltage of the transformer secondary winding.

Abstract: Disclosed examples include multiple output DC to DC converters with a buck converter including a half bridge switching circuit and transformer primary winding to provide a first output voltage signal, as well as a boost converter to provide an isolated second output voltage signal. The boost converter includes a transformer secondary winding magnetically coupled with the primary winding to provide a boost converter inductor, a switching circuit, an output diode providing the second output voltage signal, and a PWM controller that synchronizes the boost converter switching with the low side switch of the buck converter based on a sensed voltage of the transformer secondary winding.

Abstract: Described examples include DC to DC converters and systems with switching circuitry formed by four series-connected switches, inductors connected between the ends of the switching circuitry and corresponding output nodes, and with a flying capacitor coupled across interior switches of the switching circuitry and a second capacitor coupled across the ends of the switching circuitry. A control circuit operates the switching circuit to control a voltage signal across the output nodes using a first clock signal and a phase shifted second clock signal to reduce output ripple current and enhance converter efficiency using valley current control. The output inductors are wound on a common core in certain examples.

Abstract: A transducer has an input and produces a mechanical output, wherein the magnitude of the mechanical output of the transducer is dependent on the frequency and magnitude of current at the input. A driver for the transducer includes a device having a transfer function associated with the device, the device having a device input and a device output, the device output being connectable to the input of the transducer and the device input being connectable to a power source. The device attenuates the current output at a frequency that causes a peak in the magnitude of the mechanical output of the transducer.

Abstract: A transducer has an input and produces a mechanical output, wherein the magnitude of the mechanical output of the transducer is dependent on the frequency and magnitude of current at the input. A driver for the transducer includes a device having a transfer function associated with the device, the device having a device input and a device output, the device output being connectable to the input of the transducer and the device input being connectable to a power source. The device attenuates the current output at a frequency that causes a peak in the magnitude of the mechanical output of the transducer.

Abstract: A transducer has an input and produces a mechanical output, wherein the magnitude of the mechanical output of the transducer is dependent on the frequency and magnitude of current at the input. A driver for the transducer includes a device having a transfer function associated with the device, the device having a device input and a device output, the device output being connectable to the input of the transducer and the device input being connectable to a power source. The device attenuates the current output at a frequency that causes a peak in the magnitude of the mechanical output of the transducer.

Abstract: A gate driving circuit includes a driving stage configured to receive an input signal and generate a gate drive signal for a gate of a transistor switch. The gate driving circuit also includes an LC circuit having an inductor and a gate capacitance of the transistor switch. The LC circuit is configured so that a pulse in the gate drive signal generates a ringing in the LC circuit at a resonance frequency of the LC circuit to transfer energy into and out of the gate capacitance of the transistor switch. A switch could selectively couple the gate of the transistor switch to ground in order to discharge the gate capacitance. A control circuit could be used to provide the input signal, and the control circuit could be configured to regulate a duty cycle of the gate drive signal by adjusting an off-time between consecutive pulses in the input signal.

Abstract: A converter circuit includes a primary side having a resonator and a first control circuit configured to control the resonator. The converter circuit also includes a secondary side having a resonant rectifier and a second control circuit configured to control the resonant rectifier. The converter circuit further includes a transformer configured to electrically isolate the primary side from the secondary side. The second control circuit is configured to turn the resonant rectifier on and off. The first control circuit may be configured to detect when the resonant rectifier is off and, in response, turn the resonator off without using a feedback signal from the secondary side. The first control circuit may be configured to detect when the resonant rectifier is off by detecting when input power to the primary side decreases. The resonant rectifier could be turned on and off by detuning the resonant rectifier.