Linear Technology Corporation

Analog Devices International Unlimited Company

Xu Zhang

Jian Li

Zhouyuan Shi

San Hwa Chee

Yi Ding Gu

Yingyi Yan

Charles Finger

A power domain isolation system, such as without requiring a transformer, can include a reactive circuit, an input network having first and second input nodes that are coupled in parallel with the reactive circuit via respective first and second current control circuits, and an output network having first and second output nodes that are coupled in parallel with the reactive circuit via respective third and fourth current control circuits. The first and second current control circuits can be configured to couple the reactive circuit to the input nodes when the third and fourth current control circuits are configured to electrically isolate the reactive circuit from the output nodes, and the first and second current control circuits can be configured to electrically isolate the reactive circuit from the input nodes when the third and fourth current control circuits are configured to couple the reactive circuit to the output nodes.

Switching converter for power domain separation

Methods and systems of controlling a switched capacitor converter are provided. Upon determining that a voltage across a flying capacitor is above a first threshold, a first current is drawn from a first terminal of the flying capacitor by a first current source, and a second current is provided to a second terminal of the flying capacitor by a second current source. Upon determining that the voltage across the flying capacitor is below a second threshold, the first current is provided to the first terminal of the flying capacitor by the first current source, and the second current is drawn from the second terminal of the flying capacitor by the second current source. Upon determining that the voltage across the flying capacitor is above the second threshold and below the first threshold from the reference voltage, the first and second current sources are turned OFF.

Balancing charge pump circuits

Methods and systems of pre-balancing a switched capacitor converter are provided. A first comparator includes a positive input configured to receive a voltage across an output capacitor and a negative input configured to receive a first hysteresis voltage. A second comparator includes a positive input configured to receive a voltage across an input capacitor of the switched capacitor converter and a negative input configured to receive a second hysteresis voltage. A first current source is coupled between the output capacitor and GND and is configured to discharge the output capacitor upon determining that the voltage across the output capacitor is above a tolerance provided by the first hysteresis voltage. A second current source is coupled between the input capacitor and GND and is configured to discharge the input capacitor upon determining that the voltage across the input capacitor is above a tolerance provided by the second hysteresis voltage.

Balancing techniques and circuits for charge pumps

A method and system of driving a switched capacitor converter having a plurality of switches. A first driver coupled to a first switch is powered by providing a first reference voltage level VCC to a first supply and a GND reference to a second supply node of the first driver. A second driver coupled to a second switch is powered by providing a unidirectional path between the first supply node of a first driver and the first supply node of the second driver and by keeping OFF the second switch while turning ON the first switch. A third driver coupled to a third switch is powered by providing a unidirectional path between the first supply node of a second driver and the first supply node of the third driver and by keeping OFF the first and third switch while turning ON the second switch.

Driving charge pump circuits

A switched capacitor converter includes a primary switching circuit, a flying capacitor circuit, and a secondary switching circuit. The primary switching circuit includes plurality of switching transistors in series. The flying capacitor circuit includes one or more flying capacitors with each flying capacitor connected to a switching transistor. The secondary switching circuit includes two or more switching transistors and provides a first path for charging and a second path for discharging the flying capacitors. At startup, the flying capacitors are discharged via a first current source while the switching transistors are turned off. After discharging, the flying capacitors are charged via a second current source, while a first switching transistor of the primary switching circuit is kept turned off and the rest of the switching transistors perform switching according to a switching cycle. After charging, the switched capacitor converter may enter a steady state operation.

Reverse capacitor voltage balancing for high current high voltage charge pump circuits

An inductor current-sensing circuit for measuring a current in an inductor includes (a) a first RC network coupled between a first terminal of the inductor and a reference voltage source; and (b) a second RC network coupled between a second terminal of the inductor and the reference voltage source. The first RC network and the second RC network each have a time constant substantially equal to the ratio between the inductance and the DC resistance of the inductor. The inductor which current is being measured may be a primary inductor of a four-switch buck boost converter receiving an input voltage and providing an output voltage.

DCR inductor current-sensing in four-switch buck-boost converters

In a current mode switching power supply, current through the inductor needs to be sensed to control the peak current. The inductor current includes a DC component and an AC component containing switching noise. To reduce the switching noise, the actual inductor current is sensed to generate a signal, and a first AC component is attenuated by a first RC circuit while not attenuating a first DC component. A second AC component is derived by applying the rectangular wave switch voltage, which is at the duty cycle of the regulator, to a second RC filter, which blocks a second DC component. The second AC component is much larger than the first AC component and does not contain switching noise. The large second AC component, the smaller 'noisy' first AC component, and the first DC component are applied to the first RC circuit to create a low-noise inductor current signal.

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Milpitas, CA, United States of America

Xu Zhang