stk672-442b-e Sanyo Semiconductor Corporation, stk672-442b-e Datasheet - Page 16

• Manufacturer Part Number: stk672-442b-e
• Description: 2-phase Stepping Motor Driver
• Manufacturer: Sanyo Semiconductor Corporation

4. Calculating STK672-442B-E HIC Internal Power Loss
The average internal power loss in each excitation mode of the STK672-442B-E can be calculated from the following
formulas. *1
[Each excitation mode]
2-phase excitation mode
2PdAVex= 2×Vsat×0.5×CLOCK×I OH ×t2+0.5×CLOCK×I OH × (Vsat×t1+Vdf×t3) --------------------------- (4-1)
1-2 Phase excitation mode
1-2PdAVex= 2×Vsat×0.25×CLOCK×I OH ×t2+0.25×CLOCK×I OH × (Vsat×t1+Vdf×t3) ---------------------- (4-2)
W1-2 Phase excitation mode
W1-2PdAVex=0.64[2×Vsat×0.125×CLOCK×I OH ×t2+0.125×CLOCK×I OH × (Vsat×t1+Vdf×t3)] ---------- (4-3)
2W1-2 Phase excitation mode
2W1-2PdAVex=0.64[2×Vsat×0.0625×CLOCK×I OH ×t2+0.0625×CLOCK×I OH × (Vsat×t1+Vdf×t3)] ------ (4-4)
4W1-2 Phase excitation mode
4W1-2PdAVex=0.64[2×Vsat×0.0625×CLOCK×I OH ×t2+0.0625×CLOCK×I OH × (Vsat×t1+Vdf×t3)] ------ (4-5)
Motor hold mode
HoldPdAVex= 2×Vsat×I OH ---------------------------------------------------------------------------------------------- (4-6)
t1, t2, and t3 represent the waveforms shown in the figure below.
Note: 2-phase 100% conductance is assumed in Equation (4-6).
Vsat: Combined voltage of Ron voltage drop + current detection resistance
Vdf: Combined voltage of the FET body diode + current detection resistance
CLOCK: Input CLOCK (HIC: input frequency at Pin 12)
t1: Time required for the winding current to reach the set current (I OH )
t2: Time in the constant current control (PWM) region
t3: Time from end of phase input signal until inverse current regeneration is complete
t1= (-L/(R+0.25)) In (1-(((R+0.25)/V CC ) ×I OH )) --------------------------------------------------------------- (4-7)
t3= (-L/R) In ((V CC +0.25)/(I OH ×R+V CC +0.25)) -------------------------------------------------------------- (4-8)
V CC : Motor supply voltage (V)
L: Motor inductance (H)
R: Motor winding resistance (Ω)
I OH : Motor set output current crest value (A)
Motor COM Current Waveform Model
STK672-442B-E
t1
t2
t3
I OH
0A
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