Brake drive control device provided with abnormality detection function

A brake drive control circuit comprising:

• a plurality of semiconductor circuits which can turn on/off drive signals to a brake which is provided at a servo motor, and are connected in series with said brake;
• a plurality of control devices which generate brake signals which can independently turn on/off said semiconductor circuits are provided respectively connected to the plurality of said semiconductor circuits;
• a voltage detection circuit which detects the presence of voltage which is applied to said brake is provided connected in parallel to said brake;
• and
• test pulse generating circuits which introduce test pulses which instantaneously turn off said semiconductor circuits into said brake signals, respectively provided with the plurality of said control devices;
• wherein
• said control devices transmit said brake signals which turn all of said semiconductor circuits off when engaging said brake to said semiconductor circuits and transmit said brake signals which turn all of said semiconductor circuits on when disengaging said brake to said semiconductor circuits,
• the plurality of said test pulse generating circuits introducing said test pulses in said brake signals while giving time differences when disengaging said brake, and
• said voltage detection circuit detecting any malfunction of said semiconductor circuits by detecting said test pulses when disengaging said brake.