ST1115C/ST1115D Version Issue Date File Name Total Pages : A.005 : 2004/06/30 : SP-ST1115CD-A.005.doc : 13 PWM Speed Control Double Coil Brushless DC Motor Driver SILICON TOUCH TECHNOLOGY INC. 新竹市科學園區展業一路九號七樓之一 9-7F-1 Prosperity Road I Science-Based Industrial Park Hsinchu, Taiwan 300, R.O.C. Tel：886-3-5645656 Fax：886-3-5645626 點晶科技股份有限公司 ST1115C/ST1115D SILICON TOUCH TECHNOLOGY INC. ST1115C/ST1115D PWM Speed Control Double Coil Brushless DC Motor Driver General Specifications The ST1115 serial IC is a driver with pulse-width modulated (PWM) speed control for two-phase unipolar DC brushless fan applications. The device is used as an interface between a HALL effect latch and a double coil load. Besides its high-efficiency driving capability, the ST1115 has various functions such as rotation detection (for ST1115C only), tachometer signal output (for ST1115D only), linear fan speed control, exterior PWM control, locked-rotor protection and self-restart. The speed command can be either a PWM signal or simply a voltage reference according to the applications. For the temperature-proportional fan speed control, the voltage command can be generated by an external temperature sensor, typically a thermistor-resistor divider. If the motor rotation is stalled by external force or obstacles, overdrive current (or lock current) may incur coil overheat/burning. To prevent coil overheat/burning, this device incorporates locked-rotor protection circuitry to shut down the drivers. After the motor locking is released, the drivers can be automatically powered up by the internal self-restart circuitry. Features and Benefits z z z z z z z High-efficiency PWM fan speed control Linear temperature-speed control with minimum external circuitry High output sinking current capability Lock protection and automatic self-restart Tachometer output Directly connectable to a HALL Latch IC Thin, highly reliable package ( SOP8, MSOP8 ) SP-ST1115CD-A.005 Version：A.005 Page：1 點晶科技股份有限公司 ST1115C/ST1115D SILICON TOUCH TECHNOLOGY INC. Pin Assignment GND O1 FGR VDD CF O2 VT HIN Pin NO. Pin Name Description 1 GND Ground 2 FGR Rotation Detection Output (for ST1115C) Fan Tachometer Output (for ST1115D) 3 CF Lock Timing Capacitor 4 VT Input pin for PWM duty control 5 HIN Input pin from Hall Latch IC 6 O2 Output driver 2 7 VDD Power supply 8 O1 Output driver 1 Absolute Maximum Ratings Characteristic ( TA=25℃ ) Symbol Rating Unit Supply Voltage VDD 14 V Input Voltage VIN VDD+0.4 V Output Current at Lock IOUT 1000 mA Output Current at Operating IOPR 600 mA Power Dissipation (SOP8) PD 0.68 W Power Dissipation (MSOP8) PD 0.48 W Operating Temperature Range TA -40 ~ 125 °C Storage Temperature Range TS -65 ~ 150 °C SP-ST1115CD-A.005 Version：A.005 Page：2 點晶科技股份有限公司 ST1115C/ST1115D SILICON TOUCH TECHNOLOGY INC. Electrical Characteristic Characteristic ( TA = 25℃ & VDD = 12 V ) Sym. Condition Min. Limit Typ. Max. Unit Supply Voltage VDD Operating 3 12 14 V Quiescent Current IDD No load, All Inputs = 0V or VDD - 3 - mA HIN Input Terminal Input Voltage “H” VIH - 10 - 12.4 V Input Voltage “L” VIL - -0.4 - 1.5 V Input Current “H” IIH VIN = VDD - - ±1 μA Input Current “L” IIL VIN = 0 V - ±0.3 ±0.5 mA - - - mV - 250 O1 / O2 Output Terminal ( TJ = 25℃) Output Voltage High VOH Output Voltage Low VOL IOUT = 250mA mV FG Open-Drain Terminal ( TJ = 25℃) Output Leakage Current ILeak VFG =12V - - 10 μA Output Current IFG VFG = 0.2V 10 - - mA - - 15 V Output Voltage High VFGOH - VT PWM Speed Control Terminal ( TJ = 25℃) VT Threshold Voltage VTHL 100% PWM Duty Cycle - 3.88 - V VT Threshold Voltage VTHH 50% PWM Duty Cycle - 3.18 - V - 2.5*CF - sec Lock Protection and Restart Lock Protection Time TOFF Ratio of Protection Time to Restart Time RLOCK SP-ST1115CD-A.005 The capacitor connected to the CF pin is of value CF μF . TOFF / TON Version：A.005 3 Page：3 點晶科技股份有限公司 ST1115C/ST1115D SILICON TOUCH TECHNOLOGY INC. HIN Input and the Output Driver States HIN O1 O2 H OFF ON L ON OFF Internal PWM Duty Cycle v.s. VT Input Different voltage levels of the VT pin correspond to different internal PWM duty cycles. The relation of VT v.s. Duty Cycle is shown below, which illustrates a linear relation within the range of 3.18~3.88 V (VDD= 12 V). If the linear temperature control is desired, the VT terminal is biased in this linear region through a thermistor-resistor divider. In this way, the fan speed can vary linearly with respect to the temperature variation; the higher temperature results in the faster speed. Additionally, applying the exterior PWM command to the VT terminal can also control the fan speed. Note that the low level and high level of the exterior PWM command must be lower than 3.18 V and higher than 7.7 V (VDD= 12 V), respectively. The exterior PWM is active low. PWM Duty Ratio v.s. VT voltage Active Duty (%) 100% 50% 0% 3.18 3.88 7.7 12 Volt Voltage of VT ( VDD=12 Volt) SP-ST1115CD-A.005 Version：A.005 Page：4 點晶科技股份有限公司 ST1115C/ST1115D SILICON TOUCH TECHNOLOGY INC. Application Circuits and Designer’s Notes 1. Temperature-sensing fan speed control ―Refer to Figure 1. POWER VDD 75 ohm D1 VDD R1 HALL IC VT HIN Thermistor CF GND COM O1 VT CF FGR LOCK DETECTION and PROTECTION LOGIC BLOCK + - O2 PWM CONTROL R2 Figure 1. Fan speed control by the external temperature sensor. (1) If the linear temperature control is desired, the VT terminal is connected to a thermistor-resistor divider, as shown in Fig. 1. In this way, the fan speed can vary linearly with respect to the temperature variation; the higher temperature results in the faster speed. (2) Figure 2 illustrates the desired temperature-speed curve. Assume that the resistance of the thermistor is RT1 when the temperature is at T1, and RT2 at T2. Also assume that the voltage V1 applied to the VT pin will result in the fan speed rpm1, and V2 applied to the VT pin yielding rpm2. Note that the relation between the VT voltage and the fan speed depends on the size and the coil impedance of the fan. To obtain the desired temperature-speed curve, the resistance values of R1 and R2 in Fig. 1 can be roughly selected by the following equations. SP-ST1115CD-A.005 Version：A.005 Page：5 點晶科技股份有限公司 ST1115C/ST1115D SILICON TOUCH TECHNOLOGY INC. R2 = V1(V2 - VDD )R T2 + V2(VDD - V1)R T1 VDD (V1 - V2) R1 = (VDD − V1)(R T1 + R2) V1 where VDD denotes the voltage at the VDD pin, see Fig. 1. Normally, VDD is around 10.8 Volt, which may slightly vary with the variation of the driving current. Fan Speed rpm2 rpm1 T1 T2 Temperature Figure 2. Desired Temperature-Speed Curve (3) The FGR pin provides the rotation detection output for ST1115C and the tachometer output for ST1115D. FGR is an open-drain output with a built-in 100k Ω pullup resistor. An additional resistor can be used to pull up the FGR voltage to the appropriate level, which depends on the voltage level of the monitoring/control system. SP-ST1115CD-A.005 Version：A.005 Page：6 點晶科技股份有限公司 ST1115C/ST1115D SILICON TOUCH TECHNOLOGY INC. 2. Temperature-control Fan Switch ―Refer to Figure 3. Analog Power Digital Power D1 R6 R7 C2 VDD VSS R2 R3 RD Hall IC ST1115C VSS R1 RD Hin VT R4 O1 Q1 O2 CF Q2 GND Thermistor VSS Z1 C1 R5 VSS VSS VSS Z2 VSS VSS Figure 3. Temperature-control Fan Switch (where ST1115C is shown for illustration). (1) Figure 3 shows the temperature-control fan switch circuit, where the fan either stops or rotates at the full speed, depending on some temperature threshold. Figure 4 indicates the graph of the fan speed as a function of the temperature. The temperature threshold is T with the hysteresis T2-T1. Figure 4. SP-ST1115CD-A.005 Version：A.005 Page：7 點晶科技股份有限公司 ST1115C/ST1115D SILICON TOUCH TECHNOLOGY INC. 3. Fan speed control by the PWM command ―Refer to Figure 5. Analog Power Digital Power D1 R3 C2 1u 75 VSS RD Hall IC R2 R4 10K VDD RD Hin ST1115C VSS VT O1 R1 PWM O2 CF Q1 GND C1 1u VSS Z1 VSS VSS Z2 VSS VSS Figure 5. Fan speed control via the PWM command. (1) Figure 5 shows the application circuit, where the fan speed is directly controlled by the PWM command. The BJT Q1 together with resistors R1 and R2 constitutes an inverting level shifter, which is responsible for translating the voltage level of the PWM command to the VDD voltage level of the drive IC. In this way, the voltage level of the PWM command can be very low, say, 2 Volt, for example. (2) For this circuit, the PWM command is active high and its frequency range is 200 Hz ~ 40 KHz. If low acoustic noise is desired, the 20 KHz~40 KHz of the PWM frequency range is recommended. SP-ST1115CD-A.005 Version：A.005 Page：8 點晶科技股份有限公司 ST1115C/ST1115D SILICON TOUCH TECHNOLOGY INC. 4.Operating as a pre-driver―Refer to Figure 6. (1) When a large fan is used, the driving current may be too large for ST1115 directly driving the fan. In this case, ST1115 may operate as a pre-driver, as illustrated in Fig. 6. Q1 and Q2 are PNP BJT, working as driving switches. The fan speed is controlled via the VT terminal, which can be connected to a thermistor-resistor divider or a PWM generator. Digital Power Analog Power D1 R3 R4 C2 VDD VSS RD Hall IC RD Hin ST1115C VSS R1 VT Q1 Q2 R2 O1 VT O2 CF GND C1 VSS VSS VSS Figure 6. ST1115 operates as a pre-driver. SP-ST1115CD-A.005 Version：A.005 Page：9 點晶科技股份有限公司 ST1115C/ST1115D SILICON TOUCH TECHNOLOGY INC. 5. Lock protection and restart timing (1) If the fan is locked, ST1115 will turn the driver off, avoiding high-current damage of the driver. After a period TOFF of turning off, it will try to restart the fan by turning the driver on for a short time TON. The proportion of TOFF to TON is around 3:1. The absolute values of TOFF and TON depend on the capacitor connected to the CF pin. (2) Assume that the capacitance of the capacitor connected to the CF pin is CF. The lock protection time is roughly 3*CF second. The recommended capacitance CF is 1μF for roughly 2.5-sec lock protection and 800-msec lock restart. 6. Power Dissipation v.s. Temperature (1) The power dissipation is affected by various factors, such as the supply voltage, the output current, and loading. It is important to ensure the applications do not exceed the allowable power dissipation of the IC package. The allowable motor driver power dissipation versus temperature is depicted as follows: Power Dissipation ( mW ) Power Dissipation-Temperature 800 750 700 650 600 550 500 450 400 350 300 250 200 150 100 50 0 SOP8 MS OP 8 0 SP-ST1115CD-A.005 25 50 75 100 Ambient Temperature ( ℃ ) Version：A.005 125 Page：10 點晶科技股份有限公司 ST1115C/ST1115D SILICON TOUCH TECHNOLOGY INC. Package Specifications SOP8 : ST1115C_TSP1 / ST1115D_TSP1 ( 8-pin SOP ) ST1115C XXXXXX* E C H θ L D 7°(4X) SYMBOL Dimensions in Millimeter Dimensions in Inches MIN NOM MAX MIN NOM MAX A 1.35 1.60 1.75 0.053 0.063 0.069 A1 0.10 － 0.25 0.004 － 0.010 A2 － 1.45 － － 0.057 － B 0.33 － 0.51 0.013 － 0.020 C 0.19 － 0.25 0.007 － 0.010 D 4.80 － 5.00 0.189 － 0.197 E 3.80 － 4.00 0.150 － 0.157 e － 1.27 － － 1.27 － * The product code “ST1115C”or “ST1115D” will be H 5.80 － 6.20 0.228 － 0.244 changed dependent on product and the lot number “XXXXXX” will also be subject to change on the L 0.40 － 1.27 0.016 － 0.050 Y － － 0.10 － － 0.004 θ 0° － 8° 0° － 8° A2 A A1 y e B package marking. MSOP8 : ST1115C_TMS1 / ST1115D _TMS1 (8-pin MSOP ) ST1115C XXXXXX* E1 E C θ L D 12°(4X) Dimensions in Millimeter A2 SYMBOL A A A1 A1 y b e Dimensions in Inches MIN NOM MAX MIN NOM MAX 0.81 0.92 1.07 0.032 0.036 0.042 0.00 － 0.10 0.000 － 0.004 A2 0.76 0.86 0.97 0.030 0.034 0.038 b 0.15 0.20 0.30 0.006 0.008 0.012 C 0.13 0.15 0.23 0.005 0.006 0.009 D 2.90 3.00 3.10 0.114 0.118 0.122 E 4.80 4.90 5.00 0.189 0.193 0.197 E1 2.90 3.00 3.10 0.114 0.118 0.122 * The product code “ST1115C”or “ST1115D” will be e － 0.65 － － 0.026 － changed dependent on product and the lot number “XXXXXX” will also be subject to change on the L 0.40 0.53 0.66 0.016 0.021 0.026 Y － － 0.10 － － 0.004 θ 0° － 6° 0° － 6° package marking. SP-ST1115CD-A.005 Version：A.005 Page：11 點晶科技股份有限公司 ST1115C/ST1115D SILICON TOUCH TECHNOLOGY INC. The products listed herein are designed for ordinary electronic applications, such as electrical appliances, audio-visual equipments, communication devices and so on. Hence, it is advisable that the devices should not be used in medical instruments, surgical implants, aerospace machinery, nuclear power control systems, disaster/crime-prevention equipments and the like. Misusing those products may directly or indirectly endanger human life, or cause injury and property loss. Silicon Touch Technology, Inc. will not take any responsibilities regarding the misusage of the products mentioned above. Anyone who purchases any products described herein with the above-mentioned intention or with such misused applications should accept full responsibility and indemnify. Silicon Touch Technology, Inc. and its distributors and all their officers and employees shall defend jointly and severally against any and all claims and litigation and all damages, cost and expenses associated with such intention and manipulation. SP-ST1115CD-A.005 Version：A.005 Page：12