GENERAL DESCRIPTION
The CN0121A is an H-Bridge Servo Amplifier designed for bi-directional operation of
permanent magnet (PM) DC motors. The control features a conservative design employing
rugged 15 amp, 80 volt output transistors. It is a linear, Class B, current limited amplifier.
When adequately heat sunk it can dissipate up to 150 watts of power. There are no safe
operating area (SOA) load restrictions, so full output current is available at any voltage. The
CN0121A also features a precision two-quadrant current sense amplifier for feedback
applications. If the CN0121A is configured as a motor speed control, the Speed Regulation
Trimpot is used to adjust for motor speed regulation. Convenient external phase
compensation is provided, making this amplifier ideal for use in position or velocity servo
applications.
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(1) TERMINAL STRIP CONNECTOR
No terminals or connectors are required on the wiring to the CN0121A. The recommended
wire size is 16-22 gauge. The terminal assignments and functions are described in the
following sections.
MOTOR OUTPUTS TERMINALS 1 & 9
The positive motor lead is connected to Terminal 1 and the negative motor lead is connected
to Terminal 9. With the motor connected in this way, when the voltage on the non-inverting
input, Terminal 7, is greater than the voltage on the inverting input, Terminal 8, the motor
will turn clockwise. When the voltage on Terminal 7 is less than the voltage on Terminal 8
the motor will turn counter-clockwise.
The output voltage across the motor is ± 25 volts with a 28 volt power supply. The maximum
motor current is 5 amps. The motor output terminals are diode clamped to ground and to the
positive supply voltage. The
CN0121A's output stages are conservatively designed, utilizing
15 amp @ 80 volt power transistors.
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