Ixys Corporation

Littelfuse, Inc.

Leonid A Neyman

Anatoliy V Tsyrganovich

Vladimir Tsukanov

Allan Ming-Lun Lin

Md Abdus Sattar

A two-terminal electronic fuse device involves two switches, four diodes, switch control circuitry, and a storage capacitor, connected in a particular topology. When AC current flows through the fuse, a charging current charges the storage capacitor. Energy stored in the storage capacitor is then used to power the switch control circuitry. If the voltage on the storage capacitor drops, then the switches are opened briefly and at the correct time. Opening the switches allows the charging current to flow. By opening the switches and charging the storage capacitor only at times of low current flow through the fuse, the disturbance of load current flowing through the fuse is minimized. If an overload current condition is detected, then the fuse has tripped and first and second switches are opened. If the capacitor does not need charging and there is no overload condition, then the switches remain closed.

Self-powered electronic fuse

Self-powered electronic fuse with storage capacitor that charges with minimal disturbance of load current through the fuse

A gate driver integrated circuit drives an output signal onto its output terminal and onto the gate of a power transistor. In a turn-on episode, a digital input signal transitions to a digital logic high level. In response, the gate driver integrated circuit couples the output terminal to a positive supply voltage terminal, thereby driving a positive voltage onto the gate of the power transistor. In response to a high-to-low transition of the digital input signal, the driver drives a negative voltage onto the output terminal and power transistor gate for a short self-timed period of time, and then couples the output terminal to a ground terminal, thereby driving the output terminal and power transistor gate up to ground potential. The output terminal and power transistor gate are then held at ground potential in anticipation of the next turn-on episode of the power transistor.

High-speed MOSFET and IGBT gate driver

In a switching converter having an inductive load, a current may flow through the body diode of a transistor even though the gate of the transistor is being controlled to keep the transistor off. Then when the other transistor of the switch leg is turned on, a reverse recovery current flows in the reverse direction through the body diode. To reduce switching losses associated with such current flows, a gate driver integrated circuit detects when current flow through the body diode rises above a threshold current. The gate driver integrated circuit then controls the transistor to turn on. Then when the other transistor of the switch leg is made to turn on, the gate driver first turns the transistor off. When the gate-to-source voltage of the turning off transistor drops below a threshold voltage, then the gate driver integrated circuit allows and controls the other transistor to turn on.

Gate driver for switching converter having body diode power loss minimization

A rectifier includes a larger Field Effect Transistor (FET) and a smaller FET (FET). A sense resistor is in series with FET's body diode between a cathode terminal and an anode terminal. If the cathode terminal voltage is greater than the voltage on the anode terminal, then body diodes of FETs are reverse biased, the FETs are controlled to be off, and there is no current flow through the rectifier. If, however, the voltage on the anode terminal becomes positive with respect to the cathode terminal, then the body diode of FETstarts to conduct and there is a voltage drop across the sense resistor. A comparator detects this condition and turns both FETs on. The rectifier is then conductive, so current can flow from the anode terminal, through the larger FET, and to the cathode terminal, with a small forward voltage drop and without passing across the sense resistor.

Low forward voltage rectifier

Within a non-isolated and efficient AC-to-DC power supply circuit: 1) a dep-FET is turned off to decouple an output voltage Vnode from a Vnode when a rectifier output signal Von the Vnode is greater than a first predetermined voltage Vand, 2) the dep-FET is enabled to be turned on so that a constant charging current flows from the Vnode and onto the Vnode when Vis less than V(provided that Vis less than a second predetermined voltage Vand provided that Vis adequately greater than V). To speed turn off and on of the dep-FET, gate charge of the dep-FET is removed and is stored in a second capacitor when the dep-FET is to be turned off, and charge from the second capacitor is moved back onto the gate of the dep-FET when the dep-FET is to be turned on.

Non-isolated AC-to-DC converter with fast dep-FET turn on and turn off

A power supply circuit includes a rectifier, a charging circuit, and a storage capacitor. An AC signal is rectified by the rectifier thereby generating a rectified signal Vbetween a Vnode and a GND node. The capacitor is coupled between an output voltage Vnode and the GND node. If Vis greater than a first predetermined voltage Vthen the Vnode is decoupled from the Vnode. If Vis below Vthen the charging circuit supplies a substantially constant charging current from the Vnode, through the charging circuit, to the Vnode, and to the capacitor, provided that Von the capacitor is below a second predetermined voltage Vand provided that Vis adequately high with respect to V. Due to the charging current, the voltage Von the storage capacitor is restored to the desired second predetermined voltage.

High-efficiency, low-power power supply circuit

A system for communicating with a host using control signals over a 1-wire interface is disclosed. The system includes a driver coupled to the host by the 1-wire interface. Control signals are transmitted from the host to the driver for decoding by the driver controller. The control signals are pulse width modulation format signals which are interpreted by the driver as binary encoded command mode signals or analog encoded command mode signals, depending upon when the signals are received in relation to a preamble pulse and a post-amble pulse.

1-wire communication protocol and interface circuit for high voltage applications

In a steady state operation mode, a charging circuit of a non-isolated AC-to-DC converter decouples an output voltage Vnode from a Vnode when the rectifier output signal Von the Vnode is greater than a first predetermined voltage Vand, 2) supplies a charging current from the Vnode and onto the Vnode when Vis less than Vprovided that an output voltage Von the Vnode is less than a second predetermined voltage Vand provided that Vis greater than V. In an initial power up operation mode, the maximum limit value of the charging current is smaller than it is during steady state operation. Due to the reduced charging currents employed during initial power up operation, less noise is injected back to the AC source and EMI filters are not required between the rectifier of the converter and the AC source.

Non-isolated AC-to-DC converter having a low charging current initial power up mode

A 1-wire communication protocol and interface circuitry for communication between a host controller and a LED driver is provided. The 1-wire communication protocol is configured such that both PWM signals and DC current setting commands for programming the LED driver may be transmitted from the host controller to the LED driver via the same 1-wire interface. The 1-wire communication protocol uses the length of the pulses (pulse width), rather than the number of pulses, to distinguish between different modes of communication (PWM signal transmission mode or command pulse transmission mode) and different commands of the same type (specific DC current programming commands, or specific average PWM drive current for the LED, within each transmission mode). Because the same 1-wire interface is used for transmitting both PWM signals and DC current commands, integrated circuits for the host controller and the LED driver do not require an additional wire or pin.

Growing community of inventors

Sunnyvale, CA, United States of America

Leonid A Neyman