Agamem Microelectronics Inc. PRELIMINARY AA51890 SERVO MOTOR CONTROLLER ■ DESCRIPTION The AA51890 is a BJT integrated circuit for servo motor control applications. It has the feature of internal circuit of maintaining constant voltage which helps stabilizing from fluctuation caused by voltage source and the ambient temperature. It can control external H-Bridge driver for large servo motor application. ■ FEATURES • Built-in voltage regulator. • Adjustable dead band range control. • Setting up the dead band by the internal constant. • Incorporates a protection circuit for "H-Bridge" driving configuration. • Small outline package – TSSOP16L. ■ APPLICATIONS • Servo motor control. • Radio controlled car, boat, and airplane. • IA products (such as air-condition). • Remote positioning. ■ BLOCK DIAGRAM ©Copyright Agamem Microelectronics Inc. 1 www.agamem.com.tw 2008/5/5 AGAMEM MICROELECTRONICS INCOPERATION RESERVES THE RIGHT TO MAKE CHANGES WITHOUT FURTHER NOTICE TO ANY PRODUCTS HEREIN TO IMPROVE RELIABILITY, FUNCTION OR DESIGN. AGAMEM DOES NOT ASSUME ANY LIABILITY ARISING OUT OF THE APPLICATION OR USE OF ANY PRODUCTS OR CIRCUIT DESRIBED HEREIN; NEITHER DOES IT CONVEY ANY LICENSE UNDER ITS PATENT RIGHTS, NOR THE RIGHTS OF OTHERS. Agamem Microelectronics Inc. PRELIMINARY AA51890 SERVO MOTOR CONTROLLER ■ PIN DESCRIPTION ○ CT POT EXTN2 GND 2 3 4 16 15 14 13 VIN OUT2 EXTN1 5 12 GND EXTP1 CST 6 7 8 11 10 9 RDB VCC RT EXTP2 OUT1 1 VREG TOP VIEW PIN NO. PIN NAME 1 RT 2 EXTP2 Connect to the base of the external PNP transistor 3 EXTN2 Connect to the base of the external NPN transistor 4 GND 5 EXTN1 Connect to the base of the external NPN transistor 6 EXTP1 Connect to the base of the external PNP transistor 7 CST 8 OUT1 Output Driver 1 (connect to motor) 9 VREG Regulated Voltage output 10 VCC Power supply pin 11 RDB Error pulse output 12 GND Ground pin 13 OUT2 Output Driver 2 (connect to motor) ©Copyright Agamem Microelectronics Inc. FUNCTION Timing Resistor Ground pin Stretcher capacitor 2 www.agamem.com.tw 2008/5/5 AGAMEM MICROELECTRONICS INCOPERATION RESERVES THE RIGHT TO MAKE CHANGES WITHOUT FURTHER NOTICE TO ANY PRODUCTS HEREIN TO IMPROVE RELIABILITY, FUNCTION OR DESIGN. AGAMEM DOES NOT ASSUME ANY LIABILITY ARISING OUT OF THE APPLICATION OR USE OF ANY PRODUCTS OR CIRCUIT DESRIBED HEREIN; NEITHER DOES IT CONVEY ANY LICENSE UNDER ITS PATENT RIGHTS, NOR THE RIGHTS OF OTHERS. Agamem Microelectronics Inc. PRELIMINARY AA51890 SERVO MOTOR CONTROLLER PIN NO. PIN NAME FUNCTION 14 VIN Input signal 15 POT Servo position voltage 16 CT Timing Capacitor ■ ABSOLUTE MAXIMUM RATINGS Ta=25℃ SYMBOL PARAMETER RATINGS UNIT VCC Supply voltage 3.2~7.5 V IO Output current 40 mA PD Power dissipation 300 mW —25~+125 ℃ TSTG Storage temperature range ■ ELECTRICAL CHARACTERISTICS Ta=25℃, Vcc=5V SYMBOL PARAMETER VCC Supply voltage ICC Operating current TEST CONDITIONS When output is OFF --- 5 7 mA When output is ON --- 7 10 mA --- 30 36 mA 2.35 2.5 2.65 V 4 --- --- mA IOUT Output current VREG Regulator output voltage Load capacitor 0.1uF IREG Regulator output current Load resistor 500Ω ©Copyright Agamem Microelectronics Inc. LIMITS UNIT MIN TYP MAX 3.2 5 7 V 3 www.agamem.com.tw 2008/5/5 AGAMEM MICROELECTRONICS INCOPERATION RESERVES THE RIGHT TO MAKE CHANGES WITHOUT FURTHER NOTICE TO ANY PRODUCTS HEREIN TO IMPROVE RELIABILITY, FUNCTION OR DESIGN. AGAMEM DOES NOT ASSUME ANY LIABILITY ARISING OUT OF THE APPLICATION OR USE OF ANY PRODUCTS OR CIRCUIT DESRIBED HEREIN; NEITHER DOES IT CONVEY ANY LICENSE UNDER ITS PATENT RIGHTS, NOR THE RIGHTS OF OTHERS. Agamem Microelectronics Inc. PRELIMINARY AA51890 SERVO MOTOR CONTROLLER ■ FUNCTIONAL DESCRIPTION (1) Voltage Regulator This circuit is composed of a band gap circuit, and outputs a 2.5-volt temperature compensated reference voltage. This reference voltage is stabilized when the supply voltage is variable. (2) Sawtooth wave & One-Shot Generator Connect a capacitor to CT pin will generate a triangular wave by constant current charging. A typical value is 0.1uF. The constant current is determined by a resistor connected to RT pin. A typical capacitor of approximately 0.1uF should be connected in parallel with the resistor to increase stability. (3) Servo Position & Over-Time logic This circuitry consists of a pulse width comparator, which compares the servo position detection signal (POT pin) from the one-shot timer (CT pin) whose period depends on the resistance of a potentiometer connected to the servo's drive shaft. This feedback is what provides the stability for the control circuitry. (4) Pulse Stretcher The difference between the servo control signal and the feedback signal is the error signal. This error signal is used to toggle the direction the current flows through the servo. The function of this pulse stretcher is to “stretch” the small error signal long enough and increases the duty cycle to the motor for it can maintain sufficient holding force. The circuit also implements a “dead band” function that prevents servo jitter and hunting. This is a range over which differences between the input and reference signals will not cause servo operation. When the signal differences exceed this “dead band” range, drive to the motor occurs. Servo’s drive shaft. The dead band will change according to the value of resistor connected to the RDB pin. (5) Directional Logic Control The comparator circuit compares pulses from the servo control input (VIN pin) and the voltage controlled pulse generator and provides either a positive or a negative output depending on whether the signal pulse width is larger or smaller than the position generator’s output pulse (POT pin). Application of this error voltage to the motor driver circuit causes the motor to turn in a direction that will minimize the error until both pulse widths are the same. (6) PWM Control This signal generated by directional logic control block is used to control a flip-flop that toggles the direction the current flows through the motor. The outputs of the flip-flop drive an external H-Bridge output driver that handles the high current going through the motor. This output of this block will be turned on or off with each input pulse based on the status of the directional ©Copyright Agamem Microelectronics Inc. 4 www.agamem.com.tw 2008/5/5 AGAMEM MICROELECTRONICS INCOPERATION RESERVES THE RIGHT TO MAKE CHANGES WITHOUT FURTHER NOTICE TO ANY PRODUCTS HEREIN TO IMPROVE RELIABILITY, FUNCTION OR DESIGN. AGAMEM DOES NOT ASSUME ANY LIABILITY ARISING OUT OF THE APPLICATION OR USE OF ANY PRODUCTS OR CIRCUIT DESRIBED HEREIN; NEITHER DOES IT CONVEY ANY LICENSE UNDER ITS PATENT RIGHTS, NOR THE RIGHTS OF OTHERS. Agamem Microelectronics Inc. PRELIMINARY AA51890 SERVO MOTOR CONTROLLER logic. The PWM drive techniques provide the benefits of reduced power dissipation, improved servo motor performance and positively affect system efficiency. (7) Output driver The output driver controls the servo current direction. For heavy load application, the EXTP1 and EXTP2 pin will be connected to the base of the external PNP transistors and the EXTN1 and EXTN2 pin will be connected to the base of the external NPN transistors. ■ TYPICAL APPLICATION EXAMPLE A. H-Bridge TRANSISTOR Driver ©Copyright Agamem Microelectronics Inc. 5 www.agamem.com.tw 2008/5/5 AGAMEM MICROELECTRONICS INCOPERATION RESERVES THE RIGHT TO MAKE CHANGES WITHOUT FURTHER NOTICE TO ANY PRODUCTS HEREIN TO IMPROVE RELIABILITY, FUNCTION OR DESIGN. AGAMEM DOES NOT ASSUME ANY LIABILITY ARISING OUT OF THE APPLICATION OR USE OF ANY PRODUCTS OR CIRCUIT DESRIBED HEREIN; NEITHER DOES IT CONVEY ANY LICENSE UNDER ITS PATENT RIGHTS, NOR THE RIGHTS OF OTHERS. Agamem Microelectronics Inc. PRELIMINARY AA51890 SERVO MOTOR CONTROLLER B. H-Bridge MOSFET Driver ■ ORDERING INFORMATION ORDER NO. PACKAGE PACKING Q’TY AA51890A TSSOP 16L TAPE & REEL 2,500ea ©Copyright Agamem Microelectronics Inc. 6 MARK CHART AA51890 XXXX A www.agamem.com.tw 2008/5/5 AGAMEM MICROELECTRONICS INCOPERATION RESERVES THE RIGHT TO MAKE CHANGES WITHOUT FURTHER NOTICE TO ANY PRODUCTS HEREIN TO IMPROVE RELIABILITY, FUNCTION OR DESIGN. AGAMEM DOES NOT ASSUME ANY LIABILITY ARISING OUT OF THE APPLICATION OR USE OF ANY PRODUCTS OR CIRCUIT DESRIBED HEREIN; NEITHER DOES IT CONVEY ANY LICENSE UNDER ITS PATENT RIGHTS, NOR THE RIGHTS OF OTHERS. Agamem Microelectronics Inc. PRELIMINARY AA51890 SERVO MOTOR CONTROLLER ■ PACKAGE DIMENSIONS ■ NOTES ON USE • The specifications for the product described in this document are for reference only. Upon actual use, therefore, please request that specifications to be separately delivered. • The application circuit examples explain typical applications of the products, and do not guarantee the success of any specific mass-production design. • Application circuit diagrams and circuit constants contained herein are shown as examples of standard use and operation. Please pay careful attention to the peripheral conditions when designing circuits and deciding upon circuit constants in the set. • Take account of common impedance when designing the earth line on a printed wiring board. ©Copyright Agamem Microelectronics Inc. 7 www.agamem.com.tw 2008/5/5 AGAMEM MICROELECTRONICS INCOPERATION RESERVES THE RIGHT TO MAKE CHANGES WITHOUT FURTHER NOTICE TO ANY PRODUCTS HEREIN TO IMPROVE RELIABILITY, FUNCTION OR DESIGN. AGAMEM DOES NOT ASSUME ANY LIABILITY ARISING OUT OF THE APPLICATION OR USE OF ANY PRODUCTS OR CIRCUIT DESRIBED HEREIN; NEITHER DOES IT CONVEY ANY LICENSE UNDER ITS PATENT RIGHTS, NOR THE RIGHTS OF OTHERS.