Test Procedure for the LV8860VGEVB Evaluation Board 1. For full speed FAN motor drive Osclloscope CURRENT PROBE AMPLIFIER Power supply A V PROBE INPUT CHANNEL + - OUTPUT 1 2 3 4 FAN Motor Table1: Required Equipment Efficiency 40V-1A 4 channel - Equipment Power supply Oscilloscope Current probe LV8860V Evaluation Board FAN Motor 1/8/2014 1 www.onsemi.com Test Procedure: Operation check 1. Connect the test setup as shown above. 2. Supply DC voltage to VCC. 3. Monitor the voltage of OUT1, OUT2 and FG with CH1, CH2 and CH3 and the waveform of output current with CH4 of the oscilloscope. Table2: Desired Results INPUT VCC=7V to 34V OUTPUT * Refer to the following waveform (4) If change of output current is not smooth when phase is changed, power efficiency needs to be optimized by connecting R6 or R7 to SSW to adjust the voltage. Typical current waveform A. Waveform without kickback (default VSSW=2V) LV8860V Full-Speed 200us/div LV8860V Full-Speed 5ms/div VOUT1 VOUT2 VOUT1 VOUT2 VFG VFG IOUT IOUT *Since the output current at phase switch is changed smoothly, the efficiency is good. Hence no adjustment of soft switch width is needed. 1/8/2014 2 www.onsemi.com B. Waveform with kickback (default VSSW=2V) LV8860V Full-Speed 100us/div LV8860V Full-Speed 2ms/div VOUT1 VOUT2 VOUT1 VOUT2 VFG VFG IOUT IOUT VOUT waveform has kickback * The direction of output current has not been changed after a phase switch and kickback occurs. Because of the reactive current, brake motion is set which degrades efficiency. And due to rapid current change, silent drive is impared as well. The following method allows smooth current flow at phase switch and improved efficiency and silent drive by widening the width of soft-switch. ・Adjustment method: (See p.17 of the Application Note for the details.) 90kΩ 60kΩ 12PIN RGL 90kΩ 13PIN SSW 60kΩ 12PIN RGL Rw 13PIN SSW 14PIN GND 14PIN GND Waveform without kickback (after adjusting to VSSW=3V) LV8860V Full-Speed 2ms/div LV8860V Full-Speed 100us/div VOUT1 VOUT2 VOUT1 VOUT2 VFG VFG IOUT IOUT VOUT waveform has no kickback 1/8/2014 3 www.onsemi.com 2. For speed controlled FAN motor drive Osclloscope CURRENT PROBE AMPLIFIER Power supply A Function generator V PROBE INPUT Hz CHANNEL CHANNEL 1 + - OUTPUT 1 2 2 3 4 FAN Motor Table3: Required Equipment Efficiency 40V-1A 4 channel 0 to 5V , 25kHz - Equipment Power supply Oscilloscope Current probe LV8860V Evaluation Board Function generator DC Motor 1/8/2014 4 www.onsemi.com Test Procedure: PWM speed control function check 1. Connect the test setup as shown above. 2. Supply DC voltage to VCC and input PWM signal to PWM terminal. *There is no specific input order. 3. Monitor the voltage of OUT1, OUT2 and FG terminal voltage with CH1, CH2 and CH3, and the output current waveform with CH4 of the oscilloscope. Table4: Desired Results INPUT OUTPUT VCC=7V to 34V * Refer to the following waveform VPWM=0V⇔5V/25KHz (Duty50%) Typical current waveform No PWM signal Input PWM signal LV8860V Full-Speed 5ms/div LV8860V Speed-Control 5ms/div VOUT1 VOUT2 VOUT1 VOUT2 VFG VFG IOUT IOUT LV8860V Speed-Control 20us/div VOUT1 VOUT2 VFG IOUT 1/8/2014 5 www.onsemi.com Test Procedure: Lock protection function check 1. Connect the test board as shown above. 2. Supply DC voltage to VCC. 3. Check the voltage of OUT1, OUT2 and RD terminal with CH1, CH2 and CH3 of the oscilloscope. 4. Stop the rotation of fan. Table2: Desired Results INPUT VCC=7V to 34V OUTPUT * Refer to the following waveform Typical current waveform Rotation FAN is Lock LV8860V Lock 5ms/div LV8860V Full-Speed 5ms/div VOUT1 VOUT2 VOUT1 VOUT2 VRD VRD LV8860V Lock 2s/div VOUT1 VOUT2 VRD FAN Lock starts FAN Lock releases automatic recovery mode FAN is still Lock (VRD keeps High signal) automatic recovery mode FAN restarts rotation (VRD changes to Low signal) 1/8/2014 6 www.onsemi.com Countermeasure: When abnormal waveform is observed. ・Distortion of OUT waveform Current limiter: It is presumable that the current limiter is active. Normal waveform is obtained by adjusting the resistance of Rf. When Hall input is small: Due to small Hall amplitude, the width of soft-switch may have affected the entire rotational domains. Please check the voltage and the Hall signal of SSW terminal to confirm whether they are above the recommendation amplitude value defined in p.18 of the application note. If they are below the recommendation amplitude value, narrow down the width of soft-switch by adjusting the voltage of SSW terminal to obtain normal waveform. 1/8/2014 7 www.onsemi.com