AN8267S

AN8267S Fan Motor Driver s Overview The AN8267S is an IC to drive the brushless DC fan motors for internally cooling or blowing the air to the office automation equipments and measuring equipmennts. (0.4) 1 2 3 4 5 6 7 8 0.1±0.1 16 15 14 13 12 11 10 9 0.9±0.25 10.09±0.3 0.9±0.25 2.05±0.2 Unit : mm s Features • Operating supply voltage range ; VCC=9.6 to 27.6V • • • • (Operable at VCC=6V to 9.6V as well) 2-phase half-wave drive, built-in power transistor Built-in lock protective function and automatic reset function Built-in thermal protective circuit (operating temperature: 150˚C typ.) Built-in rotation display function 1.27 0.4±0.25 (0.4) s Application For drive of brush-less DC fan motor 5.5±0.3 7.6±0.3 1.16-pin PANAFLAT Plastic Package (SOP016-P-0300) s Block Diagram VCC 12 C 4 OUT1 6 OUT2 10 VS 14 Hall Bias Lock Protect Automatic Reset 11 VM IN (–) IN (+) 1 16 – Hall Amp. + CTRL TSD 5 13 TSD Revolution Display 2 3 7 9 8 PGND GND RD1 RD2 B1 B2 0.1 0.2 + 0.05 – s Absolute Maximum Ratings (Ta=25˚C) Parameter Supply voltage Supply current Output current (t=0.1s ) Circuit current (Inflow current) Circuit voltage (Applied voltage) Power dissipation Operating ambient temperature Storage temperature Symbol VCC ICC IO (peak) I2, I3 V2, V3, V6, V10 PD Topr Tstg Rating 28.8 18 1.5 10 55 735 Note 1) –30 to + 80 –55 to + 150 Unit V mA A mA V mW ˚C ˚C Note 1) When mounted to the glass epoxy PCB 50 × 50 × 0.8mm s Recommended Operating Range (Ta=25˚C) Parameter Operating supply voltage range Symbol VCC Range 9.6V to 27.6V s Electrical Characteristics (Ta=25˚C) Parameter Supply current Hall amp./Common mode input voltage Input current Hall bias voltage Output saturation voltage Leak current Bound protection Ct/Charging current Bound protection Ct/Charging current Threshold value voltage (1) Threshold value voltage (2) Rotation display/Output leak current Output voltage Rotation display/Output leak current Output voltage Symbol ICC VHI IIH VHB VOsat IOleak Itc Itd VtH VtL IOL3 VOL3 IOL2 VOL2 VCC=12V, VHI=2V VCC=12V, IHB=–5mA VCC=12V, IO=0.5A VCC=12V, VO=55V VCC=12V, V4=0V VCC=12V, V4=4.3V VCC=12V, Shut off VCC=12V, Recovered VCC=12V, VOL=55V VCC=12V, IOL=5mA VCC=12V, VOL=55V VCC=12V, IOL=5mA –12 0.95 3.8 0.6 –9.5 1.3 4.1 0.95 4 5 0.9 Condition VCC=12V, RL=OPEN 2 min typ max 17 VCC –2 50 6 1.4 100 –7 1.65 4.4 1.3 10 0.4 10 0.4 Unit mA V µA V V µA µA µA V V µA V µA V s Application Circuit VCC + VCC C 12 4 6 OUT1 10 OUT2 VS 14 Hall Bias Lock Protect Automatic Reset 11 VM IN (–) IN (+) 1 16 – Hall Amp. + CTRL TSD 5 13 GND TSD Revolution Display 2 RD1 3 RD2 7 B1 9 B2 8 PGND s Pins Descriptions Pin No. 1 2 3 4 5 6 7 8 Symbol IN (–) RD1 RD2 C TSD OUT1 B1 Hall input (–) Rotation display 1 (pulse output) Rotation display 2 (H/L output) Lock protection automatic reset Thermal shutdown Motor coil output 1 Output base 1 Pin name Pin No. 9 10 11 12 13 14 15 16 Symbol B2 OUT2 VM VCC GND VS NC IN (+) Hall input (+) Output base 2 Motor coil output 2 Counter electromotive absorption Supply voltage pin Ground pin Hall bias Pin name P. GND Power ground s Supplementary Explanation • Precautions for Using the AN8267S Observe the following in order to use the AN8267S safely and properly. Operating supply voltage range : 9.6V to 27.6V 1. Maximum applied voltage to the coil output Pins6 and 10 When driving the motor, the counter electromotive power of the coil is applied to the coil output Pins6 and 10 when the output transistor is turned off. (Refer to Fig.1) With the AN8267S, see to it that this counter electromotive power will be 55V or less at maximum. 1) When using the Zener diode Connect the Zener diode between the Pin11 of the AN8267S and the power line. The counter electromotive power which can be suppressed by the Zener diode is V CC –VD +VZ. Since VCCmax.=27.6V;VZmax.= 55V– 27.6V + 0.7V=28.1V Therefore, if you keep VZ at 28V or less, the counter electromotive power will not exceed 55V. 2) When using the capacitor Connect the capacitor between the base and collector of the coil output transistor as shown in Fig.3. Counterflow Preventive Diode Hair-shaped Pulse of Counter Electromotive Power Motor Generated Voltage 14 Hall Element 55Vmax. 1 16 13 12 11 6 7 9 10 AN8267S 4 8 Output Transistor OFF ON OFF Fig.1 Coil Output Waveform (Suppressing the Counter Electromotive Power) To suppress the counter electromotive power by the moter coil to 55V at maximum, do as follows. Dull a rise Fig.3 A capacitor value is as follows. C : 1,000pF to 10,000pF C : 1000pF—10000pF This capacitor can dull a rise of the counter electromotive power of the coil output. Select the capacitor so that maximum voltage of the counter electromotive power Vmax. will not exceed 55V. Counterflow Preventive Diode Zener Diode 14 Hall Element 1 16 13 12 11 6 AN8267S 4 8 10 Fig.2 s Supplementary Explanation (Cont.) 2. Occurrence of radio noises When driving the motor with the AN8267S, radio noises (noises which come out of the radio when the motor is driven near it) may occur. The radio noises are more likely to occur as the counter electromotive power of the coil output pin rises more steeply. So, they can be eliminated by attaching the external part mentioned in 1-2) above. When the lock protective function is being activated, coil current supply/stop intervals are about 1 : 7 in terms of time ratio. Assuming the external capacitor of the Pin4 to be of 1µF, the supply/stop time ratio is about 0.3sec. : 2sec. Lock Protective Function ON/OFF Time Calculation Expression Reference Voltage 1 (V1) Reference Voltage 2 (V2) toff Steep Rise Gentle Rise ton Fig.4 3. AN8267S lock protection When the motor fan is locked, the AN8267S has a function to protect the motor and IC. (lock protection operational principle) If the motor fan is locked, a sine wave signal is not input from the Hall element any more and the potential of the Pin4 external capacitor increases. (Fig.5a) During this period, the IC is still supplying the coil current to rotate the motor fan. Then, if the voltage at the Pin4 reaches the reference voltage 1 set inside the IC, the electric charge in the external capacitor of the Pin4 is discharged constantly, thus reducing the voltage at the Pin4. (Fig.5b) The IC stops supplying the coil current when this constant current discharge starts. If the voltage at the Pin4 reaches the reference voltage 2, the IC starts charging a constant current to the external capacitor of the Pin4 and supplies the coil current again, thus repeating the above-mentioned operation. Reference Voltage 1 Fig.6 Assuming the charging current to be Ich and the discharging current to be IDC ; At charge time ; V1 –V2 = ∴t on= 1 C ∫ I ch dt = I chC· ton (V1–V2) ·C I ch At discharge time V1–V2 = ∴t off= 1 C ∫I DC dt = I ch · toff C (V1–V2) ·C IDC Each value (typ.) of the AN8267S is ; V1=4V Ich=9.5µA V2=0.95V IDC=1.3µA When C=1µF ; ton=0.32s C : External capacitor's capacity toff=2.35s 4. Rotation output Pins2 and3 The Pins2 and 3 are of open collector output. The Pin2 is a pulse output pin synchronized with a signal from the Hall element. Therefore, the Pin2 is switched over depending on the polarities of the Hall input Pins1 and 16. 1 L H 16 H L 2 H L Reference Voltage 2 a b Fig.5 The external capacitor of the Pin4 is always kept in the discharge state by a signal from the Hall element at the time of stationary rotation. Polarities of Pins2, 1, and 16 s Supplementary Explanation (Cont.) The Pin3 is switched over in synchronization with coil current supply/stop. 1. Coil current ON : 2. Coil current OFF : L H 6. Hall input Pins1 and 16 Input a sine wave signal from the Hall element to the Pins1 and 16. The input DC voltage of those pins should be 2Vmin. or more. It is recommended to connect the Hall element and DC bias resistor between the Pins1 and GND. The Hall element sine wave signal Vi to be input to the Pins1 and 16 should be ; 15mVp–p< Vi < 400mVp–p = = The maximum applied voltage for both Pins2 and 3 is 55V. 5. TSD (Thermal Shut Down)Pin5 The AN8267S incorporates the overheat protective circuit. If the chip temperature of the IC reaches 150˚C (typ.), the coil current stops. Since the Pin5 is a TSD circuit operation checking pin, leave it “open” when the motor is driving normally. 14 Hall Element 1 16 R : DC Bias Resistor AN8267S Fig.7 7. Precautions for wiring When mounting the AN8267S onto the PCB, pay attention to the following points as to its wiring. Counterflow Preventive Diode Coil Power Supply IC Power Supply 14 1 Hall Element 16 13 GND 4 8 PGND 12 Separate 11 6 10 AN8267S Separate Fig.8 • power line The power pin of the AN8267S is the Pin12. Separate it from the power line to the moter coil. Wiring to the motor coil should be made as thick and short as possible. • GND line The AN8267S has two GND Pins (8 and 13). Since the Pin8 serves as the GND pin for the coil output power transistor, separate from GND of the Pin13 as much as possible. Wiring to the Pin8 should be also as thick and short as possible.