Electronically slip-regulated vehicle brake system

An electronically slip-regulated vehicle brake system, comprising:

• an operating brake including a pressure generator that is drivable via external power, and that is configured to produce an operating brake pressure in an operating brake mode;
• an auxiliary brake including a master brake cylinder that is operable via muscle power, and that is configured to produce an auxiliary brake pressure in an auxiliary brake mode;
• a device configured to change the vehicle brake system from the operating brake mode into the auxiliary brake mode;
• a brake circuit that is connected to the master brake cylinder, and that includes:
• a return line that forms a pressure medium connection from at least one wheel brake to a reservoir tank;
• and
• a pressure reducing valve disposed in the return line and configured to control the pressure medium connection to regulate the operating brake pressure during the operating brake mode;
• a pedal travel simulator that is configured to simulate an operating travel of the master brake cylinder during the operating brake mode, and that includes a first pressure chamber and a second pressure chamber, the second pressure chamber connected to the return line of the brake system at a first position along the return line;
• and
• a simulator control valve disposed in the return line of the brake circuit at a second position downstream of the first position, and configured to control a flow of pressure medium from the master brake cylinder into the first pressure chamber of the pedal travel simulator.