US 11,121,665 B1 · Current measurement apparatus

Abstract

Integrated circuitry, such as a microcontroller, for controlling an electric motor includes circuitry for measuring a bi-directional current flowing within a coil of the electric motor. The current is sensed by an externally implemented current sensing element, such as a shunt resistor, to produce a differential voltage that is delivered to input pins of the microcontroller, which are protected by electrostatic discharge protection circuits. Current sources implemented within the microcontroller are coupled to the input pins, and work in concert with external resistors to shift the differential voltage so that it is maintained within an appropriate voltage operating range so that an accurate measurement of the bi-directional current can be made by the microcontroller.

Claims20

Dependent claims

An apparatus suitable for measuring a current in a coil of an electric motor comprising:

a shunt resistor with a first terminal adaptable for coupling to a switching element configured to provide power to the coil of the electric motor, and a second terminal adaptable for coupling to a ground potential;
a microcontroller configured to control operation of the electric motor, wherein the microcontroller comprises:
a first input pin;
a second input pin;
a first electrostatic discharge (“ESD”) protection circuit coupled to the first input pin;
a second ESD protection circuit coupled to the second input pin;
a first current source coupled between a voltage source terminal and the first input pin;
and
a second current source coupled between the voltage source terminal and the second input pin;
a first resistor coupled between the first terminal of the shunt resistor and the first input pin;
and
a second resistor coupled between the second terminal of the shunt resistor and the second input pin.

9 more elements

An integrated circuit suitable for controlling operation of an electronically commutated electric motor, the integrated circuit comprising:

circuitry configured to produce a current measurement as a function of a differential voltage signal received at first and second input pins of the integrated circuit, wherein the differential voltage signal is supplied by a current sensing element coupled to a coil of the electric motor;
a first ESD protection circuit coupled to the first input pin;
a second ESD protection circuit coupled to the second input pin;
a first current source coupled between a voltage source terminal of the integrated circuit and the first input pin;
and
a second current source coupled between the voltage source terminal and the second input pin.

3 more elements

Dependencies are inferred from the claim text.

Current measurement apparatus

Life of this patent

Current measurement apparatus

Life of this patent

Abstract

Claims20