Intersil Americas Inc.

Noel B Dequina

Paul K Sferrazza

Donald R Preslar

Robert H Isham

Weihong Qiu

M Jason Houston

A method of providing threshold voltage monitoring and control in synchronous power converters is provided. The method includes establishing a threshold voltage level for at least one of a gate drive voltage for an upper and a lower power switch in a synchronous power converter, each threshold voltage level controlling a switching delay time for one of the upper and lower power switches. The method further includes detecting body diode conduction levels for at least one of the upper and lower power switches and adjusting the threshold voltage level for at least one of the upper and lower power switches, based on the detected body diode conduction levels, to fine-tune a body diode conduction time around an equilibrium for the at least one of the upper and lower power switches.

Threshold voltage monitoring and control in synchronous power converters

An open loop modulation network for a voltage regulator including a latch network, an output sense network, a timing network, and pulse control logic. The latch network latches assertion of a pulse control signal and provides a corresponding latched control pulse indication. The output sense network detects initiation of an output pulse and provides a corresponding output pulse indication. The timing network initiates a delay period in response to the output pulse indication and resets the latched control pulse indication after expiration of the delay period. The pulse control logic terminates the output pulse after the latched control pulse indication is reset and the pulse control signal is negated, whichever occurs last. Very narrow input pulses are detected and either a minimum output pulse is generated or the output pulse is based on the pulse control signal.

System and method for open loop modulation to detect narrow PWM pulse

A method of providing threshold voltage monitoring and control in synchronous power converters is disclosed. The method establishes a threshold voltage level for at least one of an upper gate and a lower gate power switch in a synchronous power converter. The threshold voltage levels indicate switching delay times are present in the upper and lower gate power switches. The method detects body diode conduction levels for both the upper and lower gate power switches. When at least one of the detected body diode conduction levels exceed a prescribed body diode conduction level, the method adjusts the threshold voltage level for at least one of the upper and lower gate power switches to reduce a body diode conduction time for the at least one of the upper and lower gate power switches.

A method of operating a synchronous power converter generates a control signal in a load current compensation circuit based on a light load condition at the converter, where the control signal controls a gate driver for at least one power switch of the converter. When the gate driver is turned off via the control signal, the method monitors one or more comparison signals in a reference voltage adjustment module of the compensation circuit, a first comparison signal of the one or more comparison signals indicative of a voltage level at a phase node of the converter. Based on a remaining body diode conduction level associated a body diode with the at least one power switch as detected by at least a second comparison signal, the method adjusts a reference voltage for the at least one power switch with the adjustment module until the body diode is no longer conducting.

Load current compensation in synchronous power converters

A method of operating a synchronous power converter detects when at least one of an upper power switch and a lower power switch of the converter transition to an off state during a dead-time transition interval between the upper power switch and the lower power switch. The method generates a first comparison signal, indicative of a voltage level at a phase node of the converter, in a dead-time adjustment circuit coupled to the converter. The method further detects a body diode conduction level of at least one of the upper and lower power switches in the off state using at least a second comparison signal generated in the dead-time adjustment circuit and adjusts the dead-time transition interval between the upper power switch and the lower power switch using at least one current source from the dead-time adjustment circuit to reduce the dead-time transition interval to a desired dead-time interval.

Dead-time transition adjustments for synchronous power converters

A control circuit for a DC voltage supply is provided that includes a circuit, an error amplifier and modulator. The circuit is operable to measure a voltage difference between a negative voltage rail and a ground reference in the DC voltage supply. The circuit is further operative to create an offset voltage proportional with the measured voltage difference. The circuit is further yet operative to add the offset voltage to a reference voltage to create a modified reference voltage. The error amplifier has a first input coupled to receive the modified reference voltage and a second input coupled to a positive voltage rail in the DC voltage supply. The error amplifier further has an output. The modulator is coupled to the output of the error amplifier. The modulator is operative to maintain the positive rail at a select value corresponding to the modified reference voltage.

Control of a DC power supply

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-function circuit has as single input/control pin, to which respectively different values of a control input may be applied. A multi-function signal generation section is coupled to the single input/control pin and is operative to controllably generate a plurality of respectively different functional outputs, including a decoded address bit-representative output, a soft-start oscillator signal output, and a reset output, in response to application of respectively different values of the control input.

Circuit for generating precision soft-start frequency for either value of address bit applied to external reset pin

A DC power supply control apparatus monitors respective terminals supplying positive and negative DC supply voltages to a utility device. The voltage at the negative terminal is compared with a target value for that voltage to produce an offset current representative of any voltage differential therebetween. This offset current is used to produce an offset voltage, that is added to or subtracted from a target value of the positive supply voltage to produce an error amplifier reference voltage. This reference voltage is compared with the voltage at the monitored positive terminal, to produce an error voltage, in response to which the power supply's modulator loop adjusts the power supply's positive output voltage, as necessary, to maintain the intended DC voltage differential between the positive and negative DC supply voltages.

Two pin-based sensing of remote DC supply voltage differential using precision operational amplifier and diffused resistors

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

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.

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Flemington, NJ, United States of America

Noel B Dequina