Texas Instruments Corporation

Priyank Anand

Ashish Ojha

Krishnamurthy Ganapathi Shankar

Venkatesh Guduri

Ganapathi Hegde

Siddhartha Gopal Krishna

Chinmay Jain

Anand Kannan

Anand Gopalan

Clark Douglas Kinnaird

Nicholas James Oborny

Arun Tej Vemuri

Kalpana Suryawanshi

Richeek Maitra

Examples of contactor controllers, systems and methods enable quick-turn-off (QTO) using an output voltage of a contactor controller when its supply voltage is below a threshold but does not interfere with QTO when sufficient supply voltage is available. In an example, when VM loss occurs, a high-side (HS) clamp of a contactor controller is disabled, and a low-side (LS) clamp current is generated using the output voltage. The LS clamp current may be adjusted to achieve a desired QTO voltage. In another example, a HS clamp is disabled and the charging of the gate of a LS field-effect transistor (FET) is enabled only when the output voltage increases above a power-off QTO threshold (less than the LS clamp voltage); the QTO voltage is set by a voltage detection and comparison circuit of the contactor controller.

Quick turn off of contactor system during power off

In an example, a system includes a first transistor and a second transistor, the first transistor and the second transistor configured to provide current to a load. The system also includes a sense transistor coupled to the first transistor, the sense transistor configured to sense a current flowing through the first transistor. The system includes an amplifier coupled to the sense transistor, where the amplifier includes a first input, a second input, and an output. The system also includes pre-bias circuitry coupled to the amplifier, where the pre-bias circuitry is configured to provide a voltage to the first input of the amplifier responsive to the first transistor being off, where the voltage biases the amplifier.

Pre-biased dual current sensing

A control circuit regulates the propagation delay of a field effect transistor (FET) before the FET transitions to the Miller region by applying a pre-charge current for a fixed duration to the gates of the FET. After the fixed duration, the current is reduced to a lower drive current level which is based on a desired output voltage slew rate. After the FET transitions to the Miller region, the output voltage slews down in accordance with the output voltage slew rate. By regulating the slew-rate of the output voltage in the Miller region and regulating the propagation delay of the FET prior to the Miller region, the control circuit reduces electromagnetic interference (EMI) caused by the switching of the FET, thereby improving electromagnetic compatibility (EMC) of switch mode driver systems without increasing the propagation delay of the FET.

Systems and methods for regulation of propagation delay in DC motor drivers

An apparatus for regulating a slew time of an output voltage of a motor driver system includes a gate current control circuit which has a first input coupled to receive a target slew time and a second input coupled to receive a slew time. The gate current control circuit provides an incremented gate current if the slew time is greater than the target slew time and provides a decremented gate current if the slew time is less than the target slew time. The apparatus includes a gate driver which has a first input coupled to receive a PWM signal and a second input coupled to receive the gate current. The gate driver provides a gate drive signal.

Systems and methods for regulating slew time of output voltage of DC motor drivers

Disclosed is a ripple counter with a dynamic bandpass filter for a DC motor. The ripple counter includes a current sense amplifier configured to provide an analog voltage responsive to an inline current in rotor windings of the DC motor. The ripple counter also includes an analog-to-digital converter configured to provide a digital signal responsive to the analog voltage. The ripple counter also includes a digital filter configured to receive the digital signal and a clock signal and configured to vary a frequency response to provide a filtered ripple current. The ripple counter also includes a digital comparator circuit configured to receive the filtered ripple current and to provide a pulsed output. The ripple counter also includes a clock generator configured to detect the frequency of the pulsed output and to provide the clock signal responsive to the detected frequency.

Ripple counter with dynamic bandpass filter for DC motor

Examples of contactor controllers, systems and methods time-modulate levels of high-side (HS) and low-side (LS) clamp voltages in a contactor controller to switch a path through which current flows during quick-turn-off (QTO) of the contactor controller. One of the clamp voltages is at a high level and the other is at a low level. The output voltage of the contactor controller is held at the low level. The path switching may be a function of one or more parameters. In a configuration, the level of a supply voltage of the contactor controller is monitored and used to control the path switching. In a configuration, temperatures of HS and LS transistors of the contactor controller are monitored and used to control the path switching. Control of the path switching may be performed to dissipate power in a larger area to increase thermal performance of the contactor controller. Both clamps may remain active throughout the QTO process, providing redundancy and safety.

Time multiplexing voltage clamping in coil driving circuit for a contactor during quick turn off

A control circuit includes a first high-side transistor coupled between a voltage supply terminal and the first terminal of a DC motor and a second high-side transistor coupled between the voltage supply terminal and the second terminal of the DC motor. The control circuit includes a first low-side transistor coupled between a ground terminal and the first terminal of the DC motor and a second low-side transistor coupled between the ground terminal and the second terminal of the DC motor. The control circuit includes a first pull-up resistor coupled between the voltage supply terminal and a gate terminal of the first low-side transistor and a second pull-up resistor coupled between the voltage supply terminal and a gate terminal of the second low-side transistor. The pull-up resistors apply bias currents to turn ON the first and second low-side transistors to provide a conductive path to brake the DC motor.

Control circuit for passive braking for DC motor

A multiplexer comprises: a first switch; a second switch; a dummy component coupled to the first switch and the second switch and configured to: reduce a first charge injection of the first switch, and reduce a second charge injection of the second switch; and an output coupled to the first switch, the second switch, and the dummy component. A method comprises: providing an output from either a first switch or a second switch; coupling, by a dummy component, to the first switch and the second switch; using a BBM action; and reducing, by the dummy component, a first charge injection of the first switch or a second charge injection of the second switch.

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Bengaluru, India

Priyank Anand