Circuit arrangement for discharging at least one energy accumulator charged to a high voltage
A circuit arrangement discharges at least one energy store charged to a high voltage in a motor vehicle. The circuit arrangement includes a discharge circuit which is connected in parallel with the energy store and contains an auxiliary microcontroller for actuating the discharge circuit. The auxiliary microcontroller can be operated with a low voltage of 3-5 volts and contains a first voltage supply circuit for supplying the auxiliary microcontroller with the low voltage of 3-5 volts, which first voltage supply circuit is fed from a buffer capacitor with a voltage of 10-15 volts. The circuit arrangement further contains a main microcontroller, which is configured to actuate the auxiliary microcontroller so that the latter actuates the discharge circuit.
1 . A circuit configuration for discharging at least one energy store charged to a high voltage in a motor vehicle, the circuit configuration comprising:
a discharge circuit connected in parallel with the at least one energy store;
an auxiliary microcontroller for actuating said discharge circuit, said auxiliary microcontroller being operated with a low voltage of 3-5 volts;
a buffer capacitor;
a first voltage supply circuit for supplying said auxiliary microcontroller with the low voltage of 3-5 volts, said first voltage supply circuit being fed from said buffer capacitor with a voltage of 10-15 volts;
a main microcontroller configured to actuate said auxiliary microcontroller so that said auxiliary microcontroller actuates said discharge circuit;
a second voltage supply circuit, said buffer capacitor being connected, for charging, to said second voltage supply circuit, said second voltage supply circuit being connected to and supplied with power by a continuous positive voltage terminal of a vehicle battery in an electrical on-board power supply network of the motor vehicle; and
said auxiliary microcontroller being directly supplied with a voltage only by said first voltage supply circuit.
2 . The circuit configuration according to claim 1 ,
wherein said discharge circuit has a discharge resistor and a discharge transistor connected in series with said discharge resistor; and
further comprising a driver circuit, said auxiliary microcontroller being connected to said discharge circuit via said driver circuit.
3 . The circuit configuration according to claim 1 , further comprising an actuating control circuit;
further comprising a high-voltage battery; and
wherein said discharge circuit has a DC-to-DC converter, said DC-to-DC converter is connected, on an output side, to said high-voltage battery and is connected to said actuating control circuit, which is connected to said auxiliary microcontroller.
4 . The circuit configuration according to claim 3 , wherein said discharge circuit further has a discharge resistor and a discharge transistor connected in series with said discharge resistor, said discharge resistor and discharge transistor are connected in parallel with said DC-to-DC converter.
5 . The circuit configuration according to claim 1 , further comprising:
an electrically decoupled line; and
a monitoring circuit, a high potential of a high voltage is connected to said monitoring circuit, which is connected to said auxiliary microcontroller and, via said electrically decoupled line, to said main microcontroller.
6 . The circuit configuration according to claim 1 , further comprising an actuation line connected between said main microcontroller and said auxiliary microcontroller, said actuation line being electrically decoupled.
7 . The circuit configuration according to claim 3 ,
further comprising a further actuating control circuit;
further comprising a low-voltage battery; and
wherein said discharge circuit has a further DC-to-DC converter, which is connected, on an output side, to said low-voltage battery and is connected to said further actuating control circuit, said further actuating control circuit is connected to said auxiliary microcontroller.
8 . The circuit configuration according to claim 1 , wherein said discharge transistor is an insulated-gate bipolar transistor, which is connected to said driver circuit, which is connected to said second voltage supply circuit.
9 . The circuit configuration according to claim 5 , wherein said electrically decoupled line is one of a plurality of electrically decoupled lines being formed with optocouplers.