Intersil Americas Inc.

Donald R Preslar

Noel B Dequina

Paul K Sferrazza

Salomon Vulih

William Brandes Shearon

Robert H Isham

Thomas J Hayes

An over-voltage protection circuit prevents an anomaly, such as a short circuit in the upper-switched electronic device of a DC-DC power supply, from propagating to downstream circuitry. The over-voltage protection circuit, which includes an overvoltage sense resistor coupled between an output of the upper or high side FET and the gate of the lower FET, is operative to sense a short circuit fault condition in the circuit path through the upper FET during initial power up of the system. In response to this condition, the lower NFET device is turned on so as to provide an immediate by-pass of the overvoltage condition to ground, and thereby prevent excessive voltage from being applied by the output terminal to downstream powered circuitry.

Mechanism for providing over-voltage protection during power up of DC-DC converter

A multi-level current pulse generator for driving the gates of a CMOS pair implemented using a low voltage process including a multi-level pulse translator, a current amplifier circuit, and a clamp circuit. The multi-level pulse translator generates a multi-level current pulse on at least one pulse node, each current pulse having a first large current pulse with short duration followed by at least one smaller current pulse of longer duration and operative to switch the CMOS pair with reduced average power dissipation. The current amplifier circuit amplifies the current pulses provided to the gates of the CMOS pair. The clamp circuit clamps gate voltage of the CMOS pair to prevent breakdown. In a tri-level case, a first current pulse charges and discharges gate capacitance, a second current pulse stabilizes gate voltage, and a third current pulse provides a holding current level.

High voltage gate driver using a low voltage multi-level current pulse translator

A body diode comparator circuit for a synchronous rectified FET driver including a sample circuit and a comparator. The FET driver has a phase node coupled between a pair of upper and lower switching FETs and is responsive to a PWM signal having first and second phases for each cycle. The sample circuit samples an initial voltage of the phase node during the first phase of the PWM signal and provides a sum voltage indicative of the initial phase voltage added to the voltage level of the phase node during the second phase of the PWM signal. The comparator compares the sum voltage with a predetermined reference voltage and provides an output indicative of an activation state of the lower FET during the second phase of the PWM signal. The FET driver turns on the upper FET when the comparator indicates that the lower FET is off.

System and method of detecting phase body diode using a comparator in a synchronous rectified FET driver

A control circuit for a switch mode DC-DC converter contains an arrangement of monitored LGATE, UGATE and PHASE node condition threshold detectors, outputs of which are processed in accordance with a switching control operator to ensure that each of an upper FET (UFET) and a lower FET (LFET) is completely turned off before the other FET begins conduction, thereby maintaining a dead time that exhibits no shoot-through current and is independent of the type of switching FET.

PWM-based DC-DC converter with assured dead time control exhibiting no shoot-through current and independent of type of FET used

A controller for regulating a FET to operate as a pass device including input, output and gate nodes coupled to a current path input, a current path output and the gate of the FET, respectively, a controlled low current device, and an oscillating high gain regulation amplifier. The voltage source provides a regulation voltage level relative to the input node. The low current device is coupled to the gate node and has a control input. The amplifier has a first input coupled to the output node, a second input coupled to the voltage source, and an output coupled to the control input of the controlled low current device to regulate the FET. The amplifier oscillates while regulating a voltage between the input and output nodes to the regulation voltage level. The controlled low current device presents a high impedance to the gate node to prevent oscillations from disturbing regulation.

Controller for FET pass device

An over-voltage protection circuit prevents an anomaly, such as a short circuit in the upper-switched electronic device of a DC&#x2014;DC power supply, from propagating to downstream circuitry. The over-voltage protection circuit, which includes an overvoltage sense resistor coupled between an output of the upper or high side FET and the gate of the lower FET, is operative to sense a short circuit fault condition in the circuit path through the upper FET during initial power up of the system. In response to this condition, the lower NFET device is turned on so as to provide an immediate by-pass of the overvoltage condition to ground, and thereby prevent excessive voltage from being applied by the output terminal to downstream powered circuitry.

The integrated circuit includes a power driving device, and a pilot device for sensing current through the power driving device. The pilot device includes a composite pilot having a plurality of series connected transistors and which is at least active while the power driving device is in a linear mode, and a secondary pilot which is active while the power driving device is in a saturation mode. Also, a control circuit activates the secondary pilot.

Integrated circuit with current sense circuit and associated methods

The integrated circuit includes a power FET for generating an output voltage, a pilot FET for sensing current through the power driving device and generating a reference voltage, and an amplifier circuit for comparing the reference voltage of the pilot device with the output voltage of the power driving device. The amplifier circuit includes a differential pair of matched bipolar junction transistors (BJTs) having a common base. A first BJT of the differential pair being diode-connected. The amplifier circuit controls the gates of the power FET and the pilot FET.

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Hillsborough, NJ, United States of America

Donald R Preslar