Abstract: A method for synchronous serial communication includes encoding, by a master device, a header field to be initially transmitted in a frame with a header identification code and a slave count value that defines a number of slave devices communicatively coupled to the master device. A plurality of address fields to be transmitted in the frame are also encoded by the master device. Each of the address fields corresponding to a different one the slave devices. A first of the address fields to be transmitted in the frame corresponds to a last of the slave devices to receive the header field, and a last of the address fields to be transmitted in the frame corresponds to a first of the slave devices to receive the header field. The frame is transmitted to the slave devices by the master device.

Abstract: An analog signal-to-pulse width modulation (PWM) converter includes a ramp generator generating a ramp signal and a comparator circuit comparing the ramp signal to a first voltage, a second voltage, and an analog input signal. A duty cycle calculation circuit generates a first control signal to the ramp generator to generate the ramp signal. Based on signals from the comparator circuit, the duty cycle calculation circuit calculates the ratio of the time it takes for the ramp signal to exceed the analog input signal from when the ramp signal exceeds the first voltage to the time it takes for the ramp signal to exceed the second voltage from when the ramp signal exceeds the first voltage. A PWM signal generator generates a PWM output signal based on the ratio calculated by the duty cycle calculation circuit.

Abstract: In one embodiment, a method includes detecting, by a stall detection sensor in a driver coupled to a stepper motor, a first set of time-off periods in a rising commutation phase of motor current during current regulation. The stall detection sensor further detects a second set of time-off periods in a falling commutation phase of motor current during current regulation. Next, the stall detection sensor compares the first set of time-off periods with the second set of time-off periods and determines whether the stepper motor is stalled based on the comparison of the first set of time-off periods with the second set of time-off periods.

Abstract: In a described example an apparatus includes: an FET driver circuit configured to supply current to a coil in a stepper motor, the FET driver circuit configured to regulate the current to the coil using a fixed delta current; a current chopper pulse width modulated circuit coupled to the FET driver circuit configured to supply pulses corresponding to a step control signal and a direction control signal; a back electromotive force (BEMF) monitor coupled to the current chopper circuit configured to measure an off time pulse and to output a BEMF monitor signal; and a controller coupled to the current chopper pulse width modulated circuit to supply the step and direction control signals and coupled to receive the BEMF monitor signal.

Abstract: In a described example an apparatus includes: an FET driver circuit configured to supply current to a coil in a stepper motor, the FET driver circuit configured to regulate the current to the coil using a fixed delta current; a current chopper pulse width modulated circuit coupled to the FET driver circuit configured to supply pulses corresponding to a step control signal and a direction control signal; a back electromotive force (BEMF) monitor coupled to the current chopper circuit configured to measure an off time pulse and to output a BEMF monitor signal; and a controller coupled to the current chopper pulse width modulated circuit to supply the step and direction control signals and coupled to receive the BEMF monitor signal.

Abstract: A system and method for a decay lock loop for time varying current regulation in electric motors determines if a predetermined electrical current regulation level for an electric motor has been obtained within a tuning control time window. A coarse control loop increases or decreases a fast current decay, in response to a determination that the predetermined electrical current regulation level has not been obtained within the tuning control time window, until the predetermined electrical current regulation level falls within the tuning control time window. A fine control loop increments or decrements an amount of fast current decay during a total decay time, in response to a determination that the predetermined electrical current regulation level has been obtained within the tuning control time window, until a predetermined timing of the predetermined electrical current regulation level has been obtained.

Abstract: A system and method for a decay lock loop for time varying current regulation in electric motors determines if a predetermined electrical current regulation level for an electric motor has been obtained within a tuning control time window. A coarse control loop increases or decreases a fast current decay, in response to a determination that the predetermined electrical current regulation level has not been obtained within the tuning control time window, until the predetermined electrical current regulation level falls within the tuning control time window. A fine control loop increments or decrements an amount of fast current decay during a total decay time, in response to a determination that the predetermined electrical current regulation level has been obtained within the tuning control time window, until a predetermined timing of the predetermined electrical current regulation level has been obtained.

Abstract: Conventional circuits often have undesirable characteristics to due “hot spots” or use a large amount of area. Here, however, a charging circuit is provides that uses an improved driver. Namely, an amplifier within a current sensor is used to control the rate that a switch can charge an external capacitor. This is accomplished through the adjustment of the gain of the amplifier during a charging mode.

Abstract: Conventional circuits often have undesirable characteristics to due “hot spots” or use a large amount of area. Here, however, a charging circuit is provides that uses an improved driver. Namely, an amplifier within a current sensor is used to control the rate that a switch can charge an external capacitor. This is accomplished through the adjustment of the gain of the amplifier during a charging mode.