Agamem Microelectronics Inc. PRELIMINARY AA51882 SERVO MOTOR CONTROLLER ■ DESCRIPTION The AA51882 is an integrated circuit to be applied on servo motor of radio controlled operation. It provides some flexible functions to tune the servo. External H-Bridge driver will be chosen for large servo motor application. ■ FEATURES • Built-in voltage regulator. • Adjustable dead band range control by external capacitor. • Fixed pulse width setting to provide start-up power and speed control. . • 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 AA51882 SERVO MOTOR CONTROLLER ■ PIN DESCRIPTION PIN NO. PIN NAME FUNCTION 1 VREG Constant output voltage of 2.5V (typical). Make connections from this pin to a potentiometer or pulse stretcher resistor. 2 CST Connect the capacitor and resistor of the pulse stretcher section. 3 CDB Dead band setting by connecting a capacitor. 4 VIN Input signal, an adjustable pulse of 20ms cycle and 1.0-2.0ms pulse-width, operate with a positive pulse of peak value 3V or greater. RT Timing Resistor, connect a resistor that will determine the value of the constant current of this pin. A resistor of 18kΩ will yield a current of 1.0mA. 6 CT Local pulse setting, connect a capacitor that will generate a triangular wave by constant current charging. 7 MOT1 5 ©Copyright Agamem Microelectronics Inc. Output Driver 1 (connect to motor) 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 AA51882 SERVO MOTOR CONTROLLER PIN NO. PIN NAME FUNCTION 8 POT Servo position voltage from the potentiometer connected to the servo's drive shaft. 9 GND Ground pin 10 OUT1 Connect to the (Q4) base of the external NPN transistor 11 OUT2 Connect to the (Q1) base of the external PNP transistor 12 OUT3 Connect to the (Q3) base of the external NPN transistor 13 OUT4 Connect to the (Q2) base of the external PNP transistor 14 MOT2 Output Driver 2 (connect to motor) 15 VCC Power supply pin 16 CFP Fixed driving pulse setting ■ ABSOLUTE MAXIMUM RATINGS Ta=25℃ SYMBOL PARAMETER RATINGS UNIT VCC Supply voltage 3~9 V IO Output current 70 mA PD Power dissipation 500 mW －40~＋125 ℃ TSTG Storage temperature range ©Copyright Agamem Microelectronics Inc. 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 AA51882 SERVO MOTOR CONTROLLER ■ ELECTRICAL CHARACTERISTICS Ta=25℃, Vcc=5V SYMBOL PARAMETER VCC Supply voltage ICC Operating current TEST CONDITIONS LIMITS UNIT MIN TYP MAX 3.0 5 7.5 V When output is OFF --- 5 8 mA When output is ON --- 6 11 mA 2.35 2.5 2.65 V VREG Regulator output voltage Load capacitor 0.1uF IREF Reference current RT = 18 kΩ, Pin 5 current value 80 100 120 uA VINH High input voltage Pin4 3.0 --- Vcc V WSL Standard local pulse width RT = 18 kΩ, CT = 0.1 uF 1.4 1.5 1.6 ms WDB1 Minimum dead bandwidth CFP = 0.01uF, Not connect CDB --- --- 1.0 us WDB2 Standard driving band width Not connect CFP and CDB --- 2.5 6.0 us ASTR Pulse Stretcher gain RT=18 kΩ, RST=120 kΩ, CST=0.1 uF --- 100 --- times WFP Fixed driving pulse width CFP = 0.01uF, Not connect CDB 0.7 1.0 1.3 ms Standard driving pulse width Not connect CFP and CDB 0.3 0.5 0.8 ms WOP Output pulse width CST = 0.1 uF, RST = 120 kΩ, Pulse width 100uS (3pin) 8.0 10.0 12.0 ms VSAT Output pin saturation voltage ISINK = 20 mA --- 0.2 0.4 V WSDP ©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 AA51882 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 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 of 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, the servo will start to shift. The dead band will change according to the value of capacitor connected to the CDB pin. (5) Directional Logic Control The comparator circuit compares pulses from the servo control input (VIN pin) and the voltage controlled pulse generator. It 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 logic. The PWM drive techniques provide the benefits of reduced power dissipation, improved servo motor performance and positively affect system efficiency. ©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 AA51882 SERVO MOTOR CONTROLLER (7) Output driver The output driver controls the servo current direction. For heavy load application, the OUT2 and OUT4 pin will be connected to the base of the external PNP transistors and the OUT1and OUT3 pin will be connected to the base of the external NPN transistors. MOT1 and MOT2 pins are connected to PIN1 by 18kΩ resistor internally. They can be connected to both side of servo to get the better performance when servo is to be stopped. ■ TYPICAL APPLICATION EXAMPLE A. H-Bridge TRANSISTOR Driver ©Copyright Agamem Microelectronics Inc. 6 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 AA51882 SERVO MOTOR CONTROLLER B. H-Bridge MOSFET Driver VS C9 0.01uF 16 15 CFP VCC OUT4 13 VS MOT1 7 C8 103pF OUT2 11 VIN 4 Q1 Q2 M VR1 MOT2 14 5KΩ R7 1KΩ Q3 OUT3 12 Q4 OUT1 10 RT CT POT 5 6 8 RX 1KΩ CDB CST GND VREG 1 3 2 R1 470KΩ 9 R9 1MΩ R2 18KΩ C3 0.1uF C1 0.1uF C10 C2 0.001uF 0.1uF R4 150KΩ C4 0.22uF C5 4.7uF * When the servo is about to reach the target position, the servo maybe overshoot for speed issue. There are two ways to suppress such dispensable action. If MOT1 and MOT2 pins are connected to both side of servo (R9 is no need), you can try to reduce the value of R1 to let servo make an instant stop on the target position. If MOT1 and MOT2 are floating for PCB layout issue, R9 can be plugged and tuned to get the same efforts described before. The application circuit is for reference only. The value of resistor and capacitor needs to be changed and gets the best performance in various servos. Please select low threshold voltage (Vt) MOSFET driver for the maximum driving capacity. If Vt is higher, you should provide higher power supply voltage in order to turn on the MOSFET fully. ■ ORDERING INFORMATION ORDER NO. PACKAGE PACKING Q’TY AA51882A TSSOP 16L TAPE & REEL 2,500ea ©Copyright Agamem Microelectronics Inc. 7 MARK CHART AA51882 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 AA51882 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. ©Copyright Agamem Microelectronics Inc. 8 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.