Motor with input-controlled high side driver
AssigneeSGS-Thomson Microelectronics S.A.
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.
Claims7
A method of operating a polyphase DC motor having a plurality of coils, comprising the steps of:
- selecting one of a plurality of power driving transistors, each of said power driving transistors coupled to a respective coil;
- receiving a control signal which identifies either a first or a second mode of operation;
- and
- in said first mode, providing a voltage signal to a gate of the selected driving transistor such that said voltage signal varies at a first rate until the voltage on the gate of the selected power driving transistor is near a point at which the selected driving transistor will conduct and varies at a second rate, which is less than said first rate, while the transistor is conducting current to the respective coil;
- in said second mode, providing said voltage signal to the gate of the selected driving transistor such that said voltage signal varies at said first rate.
A control circuit for operating a polyphase DC motor having a plurality of coils, comprising:
- a plurality of power driving transistors for driving respective coils, each said power driving transistors driving said respective coils at rate responsive to a voltage applied to a control node of the transistors;
- a control signal which indicates either a first or a second mode of operation;
- circuitry for providing a voltage signal to a selected control node such that in said first mode of operation, said voltage signal varies at a first rate during a first phase and at a second rate, which is less than said first rate, during a second phase, and in said second mode of operation, said voltage signal varies at said first rate.
A control circuit for operating a polyphase DC motor having a plurality of coils, comprising:
- a plurality of power FET transistors each having respective source and drain regions coupled between a first voltage supply and a respective coil;
- circuitry for selecting one of said power FET transistors to apply current to its respective coil;
- a control signal which indicates either a first or a second mode of operation;
- drive control circuitry for controlling a voltage on a gate of the selected transistor, such that
- in said first mode of operation, the gate is charged to a first predetermined voltage at a first rate and to a second predetermined voltage at a second rate, which is less than said first rate, and
- in said second mode of operation, the gate is charged to said second predetermined voltage at said first rate.
Dependencies are inferred from the claim text.