Drive device of an elevator, comprising: a DC bus (2A, 2B); a motor bridge connected to the DC bus for the electricity supply of the elevator motor; which motor bridge comprises high-side and low-side switches for supplying electric power from the DC bus (2A, 2B) to the elevator motor when driving with the elevator motor, and also from the elevator motor to the DC bus (2A, 2B) when braking with the elevator motor; a control circuit of the motor bridge, with which control circuit the operation of the motor bridge is controlled by producing control pulses in the control poles of the high-side and low-side switches of the motor bridge; which drive device further comprises: a brake controller, which comprises a switch (8A, 8B) for supplying electric power to the control coil of an electromagnetic brake; a brake control circuit, with which the operation of the brake controller is controlled by producing control pulses in the control pole of the switch (8A, 8B) of the brake controller; an input circuit for a safety signal, which safety signal can be disconnected/connected from outside the drive device; drive prevention logic, which is connected to the input circuit and is configured to prevent the passage of control pulses to the control poles of the high- side and/or low-side switches of the motor bridge when the safety signal is disconnected; brake drop-out logic, which is connected to the input circuit and, is configured to prevent passage of the control pulses to the control pole of the switch (8A, 8B) of the brake controller when the safety signal is disconnected, characterized in that the signal path of the control pulses to the control poles of the high-side and/or low-side switches of the motor bridge travels via the drive prevention logic; and in that the electricity supply to the drive prevention logic is arranged via the signal path of the safety signal; and in that the signal path of the control pulses from the control circuit of the motor bridge to the drive prevention logic is arranged via an isolator. a DC bus (2A, 2B); a motor bridge connected to the DC bus for the electricity supply of the elevator motor; which motor bridge comprises high-side and low-side switches for supplying electric power from the DC bus (2A, 2B) to the elevator motor when driving with the elevator motor, and also from the elevator motor to the DC bus (2A, 2B) when braking with the elevator motor; a control circuit of the motor bridge, with which control circuit the operation of the motor bridge is controlled by producing control pulses in the control poles of the high-side and low-side switches of the motor bridge; which drive device further comprises: a brake controller, which comprises a switch (8A, 8B) for supplying electric power to the control coil of an electromagnetic brake; a brake control circuit, with which the operation of the brake controller is controlled by producing control pulses in the control pole of the switch (8A, 8B) of the brake controller; an input circuit for a safety signal, which safety signal can be disconnected/connected from outside the drive device; drive prevention logic, which is connected to the input circuit and is configured to prevent the passage of control pulses to the control poles of the high- side and/or low-side switches of the motor bridge when the safety signal is disconnected; brake drop-out logic, which is connected to the input circuit and, is configured to prevent passage of the control pulses to the control pole of the switch (8A, 8B) of the brake controller when the safety signal is disconnected, characterized in that the signal path of the control pulses to the control poles of the high-side and/or low-side switches of the motor bridge travels via the drive prevention logic; and in that the electricity supply to the drive prevention logic is arranged via the signal path of the safety signal; and in that the signal path of the control pulses from the control circuit of the motor bridge to the drive prevention logic is arranged via an isolator. a brake controller, which comprises a switch (8A, 8B) for supplying electric power to the control coil of an electromagnetic brake; a brake control circuit, with which the operation of the brake controller is controlled by producing control pulses in the control pole of the switch (8A, 8B) of the brake controller; an input circuit for a safety signal, which safety signal can be disconnected/connected from outside the drive device; drive prevention logic, which is connected to the input circuit and is configured to prevent the passage of control pulses to the control poles of the high- side and/or low-side switches of the motor bridge when the safety signal is disconnected; brake drop-out logic, which is connected to the input circuit and, is configured to prevent passage of the control pulses to the control pole of the switch (8A, 8B) of the brake controller when the safety signal is disconnected, characterized in that the signal path of the control pulses to the control poles of the high-side and/or low-side switches of the motor bridge travels via the drive prevention logic; and in that the electricity supply to the drive prevention logic is arranged via the signal path of the safety signal; and in that the signal path of the control pulses from the control circuit of the motor bridge to the drive prevention logic is arranged via an isolator.