Allegro Microsystems, LLC

Gianluca Allegrini

Thomas Ross

James McIntosh

Robert Douglas Christie

Aldo Togneri

Kamyar Khosravi

Masahira Kurihara

Yi Li

James Mcintosh

In one aspect, a circuit includes a gate driver having a first input connected to a first node and a second input connected to a second node; an epi diode connected to the first node; a switch connected to the first node; a capacitor having a top plate connected to the switch and a bottom plate connected to the second node; and a first clamp connected the first node and to the second node. The switch being open isolates the first node from negative transient effects from the top plate of the capacitor.

Gate driver isolating circuit

A system is provided for driving a load such as a multi-phase motor. The system includes a motor driver that has a plurality of switches coupled to a motor to drive a current through each of a plurality of phase coils of the motor. A polarity detection circuit detects a polarity of the current in one or more of the phase coils of the motor to generate a polarity value that represents the detected current polarity. The polarity detection circuit can include at least one comparator that has a first input coupled to a node between two of the plurality of switches, a second input coupled to receive a threshold value, and an output from which the polarity value is provided. Further included is a controller that is configured to provide a plurality of pulse width modulated (PWM) output control signals to the plurality of switches to control the switches to drive the current through the plurality of phase coils of the motor. In response to the polarity value, the controller is configured to alter a duty cycle of the plurality of PWM output control signals to modify a voltage applied to the plurality of phase coils of the motor.

Motor control system with phase current polarity detection

A charge pump includes a first power source having a voltage Vgenerated from a regulated and circuit-limiter supply, a second power source having a voltage Vand a top-off capacitor adapted to be charged to a voltage of the high of Vor Vto a limit of a voltage clamp across the top-off capacitor.

Top-off charge pump and methods of operating same

A multi-mode charge pump generates a regulated voltage at an output node from a battery input voltage. The multi-mode charge pump has a plurality of flying capacitors and a plurality of switches coupled to the flying capacitors in order to selectively couple the flying capacitors to the battery, the output node or a reference potential. The regulated voltage is provided across a storage capacitor coupled to the flying capacitors, and the regulated voltage is input to a comparator. The comparator also receives a reference voltage and compares the regulated voltage to the reference voltage to generates an asynchronous regulation signal. A controller in the multi-mode charge pump can automatically transition between operation modes such as a buck mode, a doubler mode and a tripler mode by controlling actuation of the switches in response to the asynchronous regulation signal and clock signals.

Multi-mode charge pump

Described embodiments provide a transmitter for transmitting data over a serial bus coupled to the transmitter. The transmitter includes a controller to generate data for transmission by the transmitter. A transmit driver is coupled to the controller. The transmit driver, in response to the generated data for transmission, generates logic transitions on the serial bus. The transmit driver generates low-to-high logic transitions on the serial bus by charging the serial bus by a bus current based on (i) a predetermined initial bias level for a first time period, and (ii) a first predetermined maximum bias level for a second time period. The transmit driver generates high-to-low logic transitions on the serial bus by discharging the serial bus by a bus current based on (i) a pre-charged level of the transmit driver, and (ii) a second predetermined maximum bias level for a third time period.

Non-linear transmit biasing for a serial bus transmitter

Described embodiments provide circuits, systems and methods for controlling operation of brushless direct current motors that include a plurality of windings. A gate driver provides control signals to switching elements that control a voltage applied to each of the windings of the motor. A zero crossing detector detects zero crossings of a voltage applied to the windings and transitions a zero crossing signal between a first logic level and a second logic level based on the detected zero crossings. A position estimator estimates an angular position of the motor, and counts in a first direction based on the first logic level of the zero crossing signal, and in a second direction based on the second logic level of the zero crossing signal. An observer determines a value of the counter after an elapsed time, and generates an angular position signal based upon the value of the counter.

Sensorless brushless direct current (BLDC) motor position control

A driver circuit is provided for driving a load, such as a multi-phase motor. The driver circuit includes a gate driver for providing a control signal to switching elements coupled to the driver circuit. A first switching element is coupled between a high supply voltage and a switching node of the load, and a second switching element is coupled between the switching node and a low supply voltage. To detect zero crossings of a current through the load, a zero crossing detector includes a first counter coupled to the switching node and a second counter coupled to the control signal. The first counter and second counter count in a predetermined direction based on a detected voltage of the switching node and based on a detected voltage of the control signal, respectively. The zero crossing detector generates an output signal based upon the difference between the first and the second counter.

Growing community of inventors

Musselburgh, United Kingdom

Gianluca Allegrini