DC converters with constant and variable duty ratio switching
Granted: May 31, 2011
Patent Number:
7952892
A DC converter comprises a half bridge supply circuit and one or more flyback or forward converter output circuits, and optionally also an LLC converter whose control can determine a common variable switching frequency. The half bridge supply circuit produces a 50% duty output alternating between two input voltages, such as zero and a voltage Vin. In each flyback or forward converter output circuit, a switch connects a transformer primary to the half bridge supply circuit output in a PWM…
Method and apparatus for implementing an unregulated dormant mode in a power converter
Granted: May 31, 2011
Patent Number:
7952895
A control circuit for use in a power converter with an unregulated dormant mode of operation is disclosed. In one aspect a power converter includes a drive signal generator coupled to generate a drive signal to control switching of a power switch to be coupled to the control circuit to regulate a flow of energy to a power converter output in response to an energy requirement of one or more loads to be coupled to the power converter output. An unregulated dormant mode control circuit is…
Forward converter transformer saturation prevention
Granted: May 31, 2011
Patent Number:
7952898
A control circuit for use in a power converter in one aspect limits the magnetic flux in a transformer. Controlled current sources produce a first current that is proportional to an input voltage of the power converter and a second current that is proportional to a reset voltage of the transformer. An integrating capacitor is charged with the first current and discharged with the second current, where a voltage on the capacitor is representative of the magnetic flux in the transformer. A…
Multi-stable electronic circuit state control
Granted: May 31, 2011
Patent Number:
7952341
Apparatus and methods of controlling operating states of multi-stable electronic circuits are disclosed. In one aspect, an apparatus includes a bandgap reference circuit having an operating state and a latched off state. The bandgap reference circuit includes an amplifier to provide a bandgap reference voltage when the bandgap reference circuit is in the operating state. A state control circuit is also included and is coupled to sense an output signal of the bandgap reference circuit.…
Termination and contact structures for a high voltage GaN-based heterojunction transistor
Granted: May 10, 2011
Patent Number:
7939853
A semiconductor device is provided that includes a substrate, a first active layer disposed over the substrate, and a second active layer disposed on the first active layer. The second active layer has a higher bandgap than the first active layer such that a two-dimensional electron gas layer arises between the first active layer and the second active layer. A termination layer, which is disposed on the second active layer, includes InGaN. Source, gate and drain contacts are disposed on…
Distributed power supply arrangement
Granted: May 3, 2011
Patent Number:
7936088
Distributed power supply arrangements and related methods are disclosed. Voltage is sensed at least one sense point in a power plane of a power distribution network. The power plane includes distributed source points and load points through which a plurality of power sources supply power to a plurality of loads. Currents supplied to the power plane by the power sources are regulated based on the voltage sensed at each of the at least one sense point.
Method and apparatus for a high voltage power supply circuit
Granted: May 3, 2011
Patent Number:
7936159
A control circuit for use in a power supply is disclosed. An example control circuit according to aspects of the present invention includes a signal generator coupled to generate an output signal to control switching of a power switch to be coupled to the control circuit. A feedback circuit is coupled to receive a feedback signal, which is representative of an output of the power supply during a feedback portion of an off time of the power switch. The signal generator generates the…
Method and apparatus for robust mode selection with low power consumption
Granted: May 3, 2011
Patent Number:
7936202
A low power method and apparatus for selecting operational modes of a circuit. One circuit according to the teachings of the disclosed method and apparatus includes a first current limiting circuit coupled between a selector terminal and a first voltage bus. The first current limiting circuit is adapted to vary a current limit out of the selector terminal in response to a voltage on the selector terminal. The circuit also includes a second current limiting circuit coupled between the…
Method and apparatus for reading a programmable anti-fuse element in a high-voltage integrated circuit
Granted: April 26, 2011
Patent Number:
7932738
In a method for reading a programmable anti-fuse block of a high-voltage integrated circuit a first voltage is applied to a first pin of the HVIC, the first voltage being lowered to a second voltage at a first node. Current is shunted from the first node, thereby lowering the second voltage to a third voltage. An isolation circuit block is then activated to couple the third voltage to a common node of the programmable anti-fuse block, the common node being coupled to a plurality of…
Method and apparatus for transferring energy in a power converter circuit
Granted: April 12, 2011
Patent Number:
7924132
A reduced cost energy transfer element for power converter circuits. In one embodiment, an energy transfer element according to an embodiment of the present invention includes a magnetic element having an external surface with at least a first winding and a second winding wound around the external surface of the magnetic element without a bobbin. As such, energy to be received from a power converter circuit input is to be transferred from the first winding to the second winding through a…
Method and apparatus to reduce line current harmonics from a power supply
Granted: April 12, 2011
Patent Number:
7923973
A method and apparatus for controlling a power converter. In one aspect, a controller for use in a power converter includes a first calculator coupled to determine an end of an on time of a power switch of the power converter by integrating an input current to output an on time signal representative of the end of the on time of the power switch. The controller also includes a second calculator coupled to determine an end of an off time of the power switch by integrating a difference…
Power converter with snubber
Granted: March 29, 2011
Patent Number:
7915876
A buck or boost converter, which includes a first inductor, a controlled switch, a main diode, and an output capacitor, also includes a snubber circuit to reduce losses. The snubber circuit includes a second inductor in a path in series with the switch and main diode of the converter, a series-connected resistor and diode connected directly in parallel with the second inductor, and a capacitance in parallel with the main diode and which can be constituted partly or entirely by parasitic…
Control arrangement for a PFC power converter
Granted: March 22, 2011
Patent Number:
7911812
In a PFC (Power Factor Correction) converter control unit, a PWM (pulse width modulated) signal is produced by comparing a PFC converter output voltage error signal, produced by a transconductance amplifier, with a ramp signal, which may be from a control unit of a resonant mode converter in cascade with the PFC converter. Level shifting is used to match the amplitude ranges of the compared signals. A current, representing an input current of the PFC converter and produced by a current…
Method and apparatus for limiting maximum output power of a power converter
Granted: March 1, 2011
Patent Number:
7898826
An example power converter includes a power switch, a controller, and a current offset circuit. The controller is coupled to switch the power switch between an ON state and an OFF state to regulate an output of the power converter. The controller is adapted to terminate the ON state of the power switch in response to a switch current flowing through the power switch reaching a switch current threshold. The current offset circuit is coupled to generate an offset current in response to an…
Temperature independent reference circuit
Granted: February 22, 2011
Patent Number:
7893754
A temperature independent reference circuit includes first and second bipolar transistors with commonly coupled bases. First and second resistors are coupled in series between the emitter of the second bipolar transistor and ground. The first and second resistors have first and second resistance values, R1 and R2, and third and second temperature coefficients, TC3 and TC2, respectively. The resistance values being such that a temperature coefficient of a difference between the…
Method and apparatus to limit maximum switch current in a switching power supply
Granted: February 22, 2011
Patent Number:
7894222
Techniques are disclosed to limit the current in a switch of a switching power supply. An example switching regulator circuit includes a power switch to be coupled to an energy transfer element of a power supply. A controller to generate a drive signal is coupled to be received by the power switch to control the switching of the power switch. A short on time detector is included in the controller. The short on time detector is to detect an occurrence of a threshold number of one or more…
Cascaded PFC and resonant mode power converters
Granted: February 8, 2011
Patent Number:
7885085
A control unit controls cascaded PFC and LLC converters, the LLC converter having an input coupled to an output, of the PFC converter and providing an output voltage that decreases with increasing switching frequency. The control unit produces a sawtooth waveform with a linear ramp for controlling the LLC converter switching frequency, and hence its output voltage, in dependence upon a feedback signal. It also produces for the PFC converter a PWM signal with a frequency that is the same…
Method and apparatus for power conversion and regulation
Granted: February 1, 2011
Patent Number:
7880451
Techniques are disclosed to control a power converter with multiple output voltages. One example regulated power converter includes a an energy transfer element coupled between a power converter input and first and second power converter outputs. A switch is coupled between the power converter input and the energy transfer element such that switching of the switch causes a first output voltage to be generated at the first power converter output and a second output voltage to be generated…
Method and apparatus for pulse width modulation
Granted: February 1, 2011
Patent Number:
7880523
An apparatus and method of providing a pulse width modulated signal that is responsive to a current are disclosed. A circuit according to aspects of the present invention includes a capacitor to convert a first current to a first voltage on the capacitor during a first time duration and to discharge a second current from the capacitor to change the first voltage to a second voltage during a second time duration. A comparator is also included and is coupled to an output of the capacitor…
Fault condition protection
Granted: February 1, 2011
Patent Number:
7881027
A regulator for a switched mode power supply includes switching regulator logic, a counter and a logic gate. The switching regulator logic is coupled to receive a feedback signal and to generate a switching signal in response. The feedback signal periodically cycles between a first state and a second state when the power supply operates normally. The counter is coupled to receive the feedback signal and an output of the counter indicates an auto-restart mode of the regulator in response…
