A vehicle powertrain for a hybrid vehicle includes an electronically variable transmission (EVT) with an input member to receive mechanical rotary power from the engine, an output member to provide mechanical rotary power to a vehicle powertrain to propel the vehicle, and an EVT gear train configured to selectively and operatively couple the input member to the output member. The EVT further includes first and second motor/generators driveably coupled to the gear train. A selectively engageable input brake mechanism is provided to create a reaction torque for the motor/generators thereby enabling the motor/generators to be used with additive power for electric propulsion or regenerative braking. The input brake improves electrical power to mechanical power conversion efficiency by reducing power circulation when the EVT is operated in electric drive, engine off mode.