Circuit arrangement and method for controlling a pulsed power supply
View Patent ↗Circuit arrangement for controlling a pulsed power supply having improved dynamics compared with conventional “current mode” controllers. According to the invention, the gate signal of a switch (S 1 ) is integrated. As soon as this integral value exceeds the output signal of a control amplifier (CCL), the switch (S 1 ) is switched off again. The circuit arrangement is highly suitable for economically apportioning analog switching elements and functions which are implemented by a microcontroller (uC).
1. A circuit arrangement for controlling a pulsed power supply, the circuit arrangement comprising:
an electronic switch configured to be switched on for the duration of an On time and switched off for the duration of an Off time by a control signal;
a control unit configured to:
generate the control signal; and
end the On time if a STOP-ON signal is received;
a control amplifier configured to:
receive a controlled variable, the controlled variable being related to a magnitude of a signal of the pulsed power supply; and
generate a weighted controlled variable;
a comparator configured to:
compare a time integral value of the control signal with a controlled weighted variable value; and
generate the STOP-ON signal if the time integral value of the control signal is higher than the controlled weighted variable value.
2. The circuit arrangement as claimed in claim 1 , wherein the pulsed power supply comprises an inductor and the controlled variable is related to a magnitude of current through the inductor.
3. The circuit arrangement as claimed in claim 2 , wherein the control amplifier comprises an integrating differential amplifier configured to generate a difference variable at least partly based on the controlled variable and a desired variable, wherein the weighted controlled variable is at least partly based on the difference variable.
4. The circuit arrangement as claimed in claim 3 , wherein the control unit further comprises a micro-controller configured to provide the desired variable.
5. The circuit arrangement as claimed in claim 4 , wherein the control unit is further configured to detect an output variable of the pulsed power supply and evaluate the output variable so as to establish the desired variable.
6. The circuit arrangement as claimed in claim 5 , wherein the output variable indicates the output voltage of the pulsed power supply.
7. The circuit arrangement as claimed in claim 1 , wherein the control unit is further configured to start an Off timer at the end of the On time, and this Off timer predetermines a maximum Off time in which the electronic switch is switched off, the control unit further configured to switch the electronic switch on at the end of the Off time.
8. The circuit arrangement as claimed in claim 7 , wherein the On timer and the Off timer are implemented by a microcontroller.
9. The circuit arrangement as claimed in claim 1 , wherein the control unit further comprises an On timer configured to determine a maximum On time; and the control unit is further configured to switch the electronic switch off when the maximum On time is reached.
10. The circuit arrangement as claimed in claim 1 , wherein the pulsed power supply comprises an inductor and the circuit arrangement further comprises a detector, the detector configured to transmit a STOP-OFF signal to a STOP-OFF input of the control unit in the event of a current zero crossing in the inductor; and the control unit is further configured to end the Off time and switch the electronic switch on when the STOP-OFF signal is received at the STOP-OFF input.
11. The circuit arrangement as claimed in claim 1 , wherein the pulsed power supply is a buck converter.
12. An operating device for operating high-pressure discharge lamps, wherein the operating device comprises the circuit arrangement as claimed in claim 1 .
13. A circuit arrangement for controlling a pulsed power supply, the circuit arrangement comprising:
an electronic switch configured to be switched on for the duration of an On time and switched off for the duration of an Off time by a control signal;
a control unit configured to:
generate the control signal; and
end the On time if a STOP-ON signal is received;
an inverter configured to invert the control signal; and
a comparator configured to:
compare a time integral value of an inverted control signal with a controlled variable value, wherein a controlled variable is related to a magnitude of a signal of the pulsed power supply; and
generate the STOP-ON signal if the time integral value of the inverted control signal is higher than the controlled variable value.
14. The circuit arrangement as claimed in claim 13 , wherein the pulsed power supply comprises an inductor and the controlled variable is related to a magnitude of current through the inductor.
15. The circuit arrangement as claimed in claim 14 , wherein the circuit arrangement further comprises:
a control amplifier configured to receive the controlled variable and generate a weighted controlled variable; and
wherein the comparator is configured to compare the time integral of the inverted control signal with the controlled weighted variable and generate the STOP-ON signal if the time integral value of the inverted control signal is higher than a weighted controlled variable value.