AD6392
4-CH MOTOR DRIVE IC
APPLICATION SUMMARY (Continued)
- CH4 spindle drive part
CH4 drive part is composed V-I converter and output power amplifiers.
V-I converter
Output Power AMP
Fig. 7 CH4 spindle drive part
- The V-I converter converts the input voltage applied to pin24 into a incremental output current given
by
di = Vin - Vref = Vin
100K 100K
Vin = Vin - Vref
* Vin = input voltage of pin24
*Vref = reference voltage (pin23 or pin25)
- These sourcing and sinking output current from V-I converter are delivered to output power amplifiers,
where they are appeared as differential output voltages given as:
DOF = Pref + di *170K
DOR = Pref − di *170K
- The differential voltage gain is, then, calculated as follows:
Vout = DOF - DOR = 2 * di *170K
Avf = 20log DVout = 20log 2 *170K = 10.6dB
DVin
100K
April. 2002 (Rev.0)
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