| 摘要 |
A telematics communication system (100) receives an input supply voltage (Vin) (122) from a battery (102) charged by an alternator (101) in an automotive vehicle. The telematics communication system (100) includes a transceiver (104) having a transmitter (107) and a variable delta voltage tracking regulator (VDVTR) (109). The VDVTR (109) provides a regulated output supply voltage (Vout) (124) to a power amplifier (114) in the transmitter (107) responsive to the input supply voltage (122) and a regulator control voltage (TX_EN) (123). Unfortunately, the alternator (101) generates alternator whine noise (405) that appears on the input supply voltage (122) and, in turn, appears on the regulated output supply voltage (Vout) (124). The VDVTR (109) has a first operating stage and a second operating stage, each controlled by a bias circuit (R1, R2 and R3), and a third operating stage, controlled by a voltage limiting circuit (D1). The first operating stage of the bias circuit sets the regulated output supply voltage (Vout) (124) to be equal to the input supply voltage (122) (Vout=Vin) when the input supply voltage (122) is less than or equal to a first predetermined voltage (Vmin), responsive to the regulator control voltage (123) and the input supply voltage (122), to permit the presence of the alternator whine noise (405) on the regulated output supply voltage (Vout) (124) while giving operational priority to the transmit power output level of the transmitter (107). The second operating stage of the bias circuit sets the regulated output supply voltage (Vout) (124) to be equal to a predetermined function of the input supply voltage (Vin) (122) (Vout=mVin+b) when the input supply voltage (122) is between the first predetermined voltage (Vmin) and a second predetermined voltage (Vmax), greater than the first predetermined voltage (Vmin), responsive to the regulator control voltage (123) and the input supply voltage (122), to create an increasing voltage delta (404) between the input supply voltage (122) and the regulated output supply voltage (Vout) (124), thereby reducing the alternator whine noise (404) on the regulated output supply voltage (Vout) (124) while continuing to meet operational requirements of the transmit power output level of the transmitter (107). The third operating stage sets the regulated output supply voltage (Vout) (124) to be equal to a maximum predetermined voltage (Vmax) (Vout=Vmax) when the regulated output supply voltage (Vout) (124</
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