Patent ID: 6285304
Filing Date: 2001-09-04
Classification: G01R,H03M

Abstract:
A controlled gradient amplifier for a magnetic resonance imaging system, said controlled gradient amplifier comprising:a gradient amplifier having a switched output stage which emits a gradient current;a current measurement element connected to said switched output stage, which measures said gradient current and emits an analog actual value signal corresponding thereto;a reference value generator which generates a digital reference value representing a desired value for said gradient current;a digital-to-analog converter supplied with said digital reference value from said reference value generator, which converts said digital reference value into an analog reference value signal;a differential amplifier supplied with said analog signal and supplied with said analog reference value signal from said digital-to-analog converter, which generates an analog difference signal dependent on a difference between said analog actual value signal and said analog reference value signal;an integrator supplied with said difference signal from said differential amplifier, which integrates said difference signal to generate an analog integrator signal;an analog-to-digital converter supplied with said analog integrator signal, which converts said analog integrator signal into a digital integrator value; anda regulator supplied with said digital integrator value which generates a digital adjusting value dependent at least on said digital integrator value, said regulator being connected to said switched output stage and supplying said digital actuating value thereto to actuate said switched output state.