US Patent 11400897 Towed vehicle braking system with combined vacuum and pressure supply

A towed vehicle braking system is described that in some embodiments includes a brake pedal connector configured to connect to a brake pedal of a brake of a towed vehicle. A cylinder has a piston connected to the brake pedal connector to actuate the brake of the towed vehicle through the brake pedal connector by applying a positive pressure to the brake pedal connector to move the brake pedal. A vacuum supply line is coupled to a power booster of the towed vehicle brake and configured to provide vacuum to the power booster. A pump is coupled to the vacuum supply line and to the cylinder to alternately provide vacuum to the vacuum supply line and to drive the piston to actuate the brake. An inertial sensor detects deceleration of the towed vehicle, and a processor is coupled to the inertial sensor and to the pump to cause the pump to not provide vacuum and to drive the piston in response to the detection of deceleration.