Electronic Circuit For Reducing Rotation Speed Of An Unpowered Electric Motor

A method of driving an electric motor with a motor drive circuit, comprising:

• providing a plurality of driver circuits, each one of the plurality of driver circuit comprising a high side transistor coupled to a low side transistor in a half bridge arrangement, wherein each one of the high side transistors and each one of the low side transistors has a respective control node and respective first and second current passing nodes, wherein the second current passing node of each of the high side transistors is coupled to the first current passing node of a respective one of the low side transistors at a respective junction node, wherein each one of the plurality of driver circuits is operable to drive a respective current out of a respective junction node into a respective winding of the electric motor;
• providing a capacitor coupled to the first current passing node of each one of the high side transistors;
• holding a capacitor voltage on the capacitor;
• sensing when a power supply voltage to the motor drive circuit is below a threshold voltage to identify a braking mode of operation, and when in the braking mode of operation, the method further comprises:
• turning the high side transistors off;
• generating at least one pulse signal having at least two state transitions;
• and
• communicating the at least one pulse signal to a respective at least one of the control nodes of a respective at least one of the low side transistors, resulting in on and off conditions of the at least one of the low side transistors, wherein the on condition of the at least one of the low side transistors results in the braking mode of operation during the on condition, and wherein the at least two state transitions results in a voltage boosting operation such that the capacitor voltage is a boosted voltage, the boosted voltage higher than a voltage that would be achieved without the at least two state transitions.

A motor drive circuit for driving an electric motor, comprising:

• a plurality of driver circuits, each one of the plurality of driver circuit comprising a high side transistor coupled to a low side transistor in a half bridge arrangement, wherein each one of the high side transistors and each one of the low side transistors has a respective control node and respective first and second current passing nodes, wherein the second current passing node of each of the high side transistors is coupled to the first current passing node of a respective one of the low side transistors at a respective junction node, wherein each one of the plurality of driver circuits is operable to drive a respective current out of a respective junction node into a respective winding of the electric motor;
• a capacitor coupled to the first current passing node of each one of the high side transistors, the capacitor operable to hold a capacitor voltage;
• means for sensing when a power supply voltage to the motor drive circuit is below a threshold voltage to identify a braking mode of operation, and when in the braking mode of operation, the motor drive circuit further includes;
• means for turning the high side transistors off;
• means for generating at least one pulse signal having at least two state transitions;
• and
• means for communicating the at least one pulse signal to a respective at least one of the control nodes of a respective at least one of the low side transistors, resulting in on and off conditions of the at least one of the low side transistors, wherein the on condition of the at least one of the low side transistors results in the braking mode of operation during the on condition, and wherein the at least two state transitions results in a voltage boosting operation such that the capacitor voltage is a boosted voltage, the boosted voltage higher than a voltage that would be achieved without the at least two state transitions.