发明授权
US6061258A Monitoring of current in an inductive load, PWM driven through a bridge stage 有权
监控电感负载中的电流,PWM通过桥接级驱动

Monitoring of current in an inductive load, PWM driven through a bridge
stage
摘要:
Monitoring of current flowing through an inductive load driven through a bridge power stage in a PWM mode, comprises sampling the signal output by a sensing amplifier with a Sample & Hold circuit including a sampling switch and a storing capacitor. The average value of the current in the load is monitored by sampling at a half way point of an active driving phase and at a half way point of a current recirculation phase by closing the switch with a synchronizing pulse that coincides with the half way points of these phases of operation. The monitoring uses a pair of complementary periodic reference signals and uses a sensing amplifier to amplify the signal existing on a current sensing resistor functionally connected in series with the load. This produces an amplified signal representative of the current in the load to be fed to an input of an error amplifier driving a power amplifier of the bridge stage. The synchronizing pulse is generated in coincidence with the peak and with the virtual zero crossing of the two reference periodic signals, out of phase from one another by 180 degrees. A two-input logic AND gate, combining the synchronizing pulse and a masking signal of a preestablished duration generated at every switching of the bridge stage may also be employed.
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