Stmicroelectronics Asia Pacific Pte Limited

Marvell International Limited

Marvellworld Trade Ltd.

Kong Yin Leong

Ravishanker Krishnamoorthy

Yichao Wang

Soon Hwei Tan

The amount of power being output to the load is sensed by sampling the frequency of the pulse width modulation signal that is controlling the switch that is providing the power to the load. If the pulse width modulation signal has a high frequency, then it will be providing higher power to the load. As the power drawn by the load decreases, the frequency of the pulse width modulation power supply signal will decrease. By sensing and periodically sampling the frequency of the pulse width modulation signal that is providing power, the demand of the load can be quickly and accurately determined. As the power demand of the load decreases, the peak current that the power supply switch can provide also decreases. The permitted peak current dynamically changes to adapt to the power drawn by the load.

Frequency detection to perform adaptive peak current control

Frequency detection to perform dynamic peak current control

An apparatus includes a clamp control circuit configured to control a first current to have a magnitude substantially equal to that of a second current when the second current has a first flow direction. The clamp control circuit is configured to control the first current to be substantially zero when the second current has a second flow direction. A method includes determining a value of a first current, controlling a second current to have a substantially zero value when the first current flows in a first direction, and controlling the second current to have a magnitude substantially equal to that of the first current when the first current flows in a second direction. The first current flows in the first direction when a winding of a motor is being supplied with energy and flows in the second direction when the winding of the motor is discharging energy.

Active clamp for motor driver

An apparatus includes a driver circuit and a motor control circuit. The driver receives first and second supply voltages and a control signal, and generates a target voltage on an output terminal according to the control signal. The motor control circuit is configured to generate the control signal and measure a rise time of a current of the driver circuit during a period of time in which the output terminal is at the target voltage. A method includes, during a time interval, providing the first supply voltage on an output of a first driver circuit, generating a target voltage on an output of a second driver circuit, and measuring a rise time of a current flowing between the outputs of the first and second driver circuits. For both the apparatus and method, the target voltage is between and substantially different from the first and second supply voltages.

Controlled inductive sense system

A dual supply circuit uses a dual feedback control, single inductor, dual polarity boost architecture with a low side power FET for end of current recirculation sensing. A dual feedback system tracks the output voltage variations and a low side power FET end of current recirculation sensing utilizes the internal current limit sensing system. Logic defining the state of operations allows the regulator to operate in both single and dual mode to cater to wide application ranges. The positive boost regulator can be operated in a buck mode making the output voltage constant with high input supply.

Architecture for controlling a dual polarity, single inductor boost regulator used as a dual polarity supply in a hard disk drive dual stage actuator (DSA) device

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Singapore, Singapore

Kong Yin Leong