Motor with input-controlled high side driver
AssigneeSTMicroelectronics S.r.l.
InventorFrancesco Carobolante
Life of this patent
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Abstract
A circuit for operating a polyphase DC motor, such as the type having a plurality of "Y" connected stator coils, has circuitry for charging the coils at a rate which will reduce EMI and other noise, while maintaining an acceptable charge rate. The gate of a selected high side driving transistor is charged at a relatively high rate during a ramping phase. During the ramping phase, the gates of the selected transistor is charged to a voltage near the voltage needed to form a channel in the transistor for conduction. After the ramping phase, the gates are charged at a lesser rate in order to control the rate of charging of the stator coils to prevent noise.
Claims21
A control circuit for operating a polyphase DC motor having a plurality of coils, said control circuit comprising:
- a plurality of driving transistors for driving said coils, each of said driving transistors being coupled between a voltage source and a respective one of said coils and being driven at a rate responsive to a voltage applied to a control node of said driving transistor;
- a plurality of control transistors, each control transistor having a first terminal coupled to a reference voltage and a second terminal coupled to the control node of a respective one of said driving transistors, said control transistor being structured to provide a current from said second terminal to said control node of said driving transistor, said voltage applied to said control node varying at a first rate during a first phase and at a second rate during a second phase based on the current provided from said second terminal.
A method of operating a polyphase DC motor having a plurality of coils, comprising the steps of:
- selecting one of a plurality of driving transistors, each of said driving transistors being coupled to a respective one of said coils;
- and
- providing a current from a control transistor coupled between a reference voltage and a control node of said selected driving transistor, said current being provided to said control node to control a voltage of said control node, said voltage of said control node varying at a first rate during a first phase and at a second rate during a second phase based on said current provided by said control transistor.
A control circuit for operating a polyphase DC motor having a plurality of coils, the control circuit comprising:
- a plurality of FET transistors, each FET transistor being coupled between a first voltage supply and a respective coil;
- circuitry for selecting one of said FET transistors to apply current to its respective coil;
- and
- a control transistor having a first terminal coupled to a reference voltage and a second terminal coupled to a gate of said selected FET transistor, said control transistor being structured to provide a current from the second terminal to said gate for controlling a voltage of said gate, said gate being charged to a first predetermined voltage at a first rate and subsequently being charged to a second predetermined voltage at a second rate based on the current from the second terminal of the control transistor.
A method of controlling a rate of change of voltage applied to a coil from a driving transistor coupled between a power supply and the coil, the method comprising the steps of:
- providing a first voltage to a first terminal of a control transistor;
- providing a controlled current from a second terminal of the control transistor to a control terminal of the driving transistor;
- and
- governing the controlled current based on a difference between the first voltage and a voltage of the control terminal of the driving transistor, the controlled current being provided at a first rate during a first phase and at a second rate during a second phase.
Dependencies are inferred from the claim text.