Supply circuit with ripple compensation
View Patent ↗A supply circuit ( 1 ) comprising an inductor ( 2 ) coupled to switching means ( 7 ) and comprising a capacitor ( 4 ) is provided with an impedance ( 3 ) located between the inductor ( 2 ) and the capacitor ( 4 ), with a current injector ( 5 ) and with a feedback loop comprising a converter ( 6 ) for controlling the current injector ( 5 ) for compensating a ripple in an output voltage across the capacitor ( 4 ). The impedance ( 3 ) allows injection of a compensating current at a location different from an output location. This increases a number of possible detections of ripples in the output voltage and allows a ripple in an output voltage to be detected even in case of loads introducing much noise across the capacitor ( 4 ). The converter ( 6 ) detects a detection signal via the impedance ( 3 ) by measuring a voltage across the impedance ( 3 ) or across a serial circuit comprising the impedance ( 3 ) and the capacitor ( 4 ). The impedance ( 3 ) comprises a resistor or a further inductor.
1. A supply circuit comprising:
an inductor comprising a first electrode coupled to switching means and comprising a second electrode,
an impedance comprising a third electrode coupled to the second electrode and comprising a fourth electrode,
a capacitor comprising a fifth electrode coupled to the fourth electrode and comprising a sixth electrode,
a current injector coupled to the third electrode for compensating a ripple in a voltage signal between the fifth and sixth electrodes, and
a feedback loop for detecting a detection signal via the impedance and for supplying a control signal to the current injector and comprising a converter for converting the detection signal into the control signal, the converter comprising an amplifier for amplifying the detection signal and comprising a rectifier for rectifying the amplified detection signal and comprising an integrator for integrating the rectified amplified detection signal, the control signal comprising the integrated rectified amplified detection signal.
2. The supply circuit as defined in claim 1 , inputs of the feedback loop being coupled to the third electrode and to the fourth electrode or the sixth electrode.
3. The supply circuit as defined in claim 1 , the impedance comprising a further inductor.
4. The supply circuit as defined in claim 1 , the rectifier comprising a multiplier for multiplying the amplified detection signal with a duty cycle signal.
5. The supply circuit as defined in claim 1 , the integrator comprising a multiplier for multiplying the rectified amplified detection signal with a saw tooth signal.
6. The supply circuit as defined in claim 1 , the converter further comprising one or more high pass filters for filtering the detection signal and/or for filtering the amplified detection signal.
7. The supply circuit as defined in claim 1 , wherein the switching means comprises transistors and the supply circuit being a switched mode supply circuit.
8. A device comprising the supply circuit as defined in claim 1 .