High speed controller area network receiver having improved EMI immunity
First Claim
1. A Controller Area Network (CAN) receiver comprising:
- a voltage divider coupleable to a controller area network bus for dividing a signal on the bus by a predetermined factor N to generate an input signal;
a front end amplifier coupled to the voltage divider for receiving the input signal, the front end amplifier amplifying the input signal by a predetermined factor substantially equal to 1/N; and
a reference generator coupled to the front end amplifier to receive a common-mode voltage of the front end amplifier, the reference generator generating a voltage reference output signal equivalent to the front end amplifier common-mode voltage subtracted by a bandgap reference voltage wherein the bandgap reference voltage has a first value and a second value.
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Accused Products
Abstract
A CAN receiver architecture design that provides better immunity against EMI interference than conventional designs is disclosed herein. This CAN receiver includes a voltage divider network connected to a front-end amplifier for dividing down the input signal from a two wire line by a predetermined amount and amplifying the signal by the same predetermined amount. The front-end amplifier generates the common-mode voltage of the input signal for a reference generator that determines the logic level of the incoming signal and subtracts a bandgap voltage reference from the common-mode voltage. A comparator compares the difference between the output of the front-end amplifier and the resultant signal generated by the reference generator to generate an output signal for the receiver. This CAN receiver architecture is faster than conventional designs and possesses an improved common-mode rejection, while operating over a wide input common mode range.
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Citations
18 Claims
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1. A Controller Area Network (CAN) receiver comprising:
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a voltage divider coupleable to a controller area network bus for dividing a signal on the bus by a predetermined factor N to generate an input signal; a front end amplifier coupled to the voltage divider for receiving the input signal, the front end amplifier amplifying the input signal by a predetermined factor substantially equal to 1/N; and a reference generator coupled to the front end amplifier to receive a common-mode voltage of the front end amplifier, the reference generator generating a voltage reference output signal equivalent to the front end amplifier common-mode voltage subtracted by a bandgap reference voltage wherein the bandgap reference voltage has a first value and a second value. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method of receiving signals on a Controller Area Network (CAN)
bus comprising: -
dividing a bus signal by a predetermined factor N to generate an input signal; and amplifying the input signal by a predetermined factor substantially equal to 1/N; generating a reference voltage signal equivalent to a common-mode voltage of the amplification step; generating a reference voltage output signal by subtracting a bandgap reference voltage from the reference voltage signal, wherein the bandgap reference voltage can have a first value. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18)
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Specification