TB62206FG Datasheet, PDF (15/27 Pages) Toshiba Semiconductor – BiCD PWM 2−Phase Bipolar Stepping Motor Driver

TB62206FG
IC Power Dissipation
IC power dissipation is classified into two: power consumed by transistors in the output block and power
consumed by the logic block and the charge pump circuit.
• Power consumed by the Power Transistor (calculated with RON = 0.60 Ω)
• In Charge mode, Fast Decay mode, or Slow Decay mode, power is consumed by the upper and lower
transistors of the H bridges.
The following expression expresses the power consumed by the transistors of a H bridge.
P (out) = 2 (Tr) × IOUT (A) × VDS (V) = 2 × IOUT2 × RON ..............................(1)
The average power dissipation for output under 4-bit micro step operation (phase difference between
phases A and B is 90°) is determined by expression (1).
Thus, power dissipation for output per unit is determined as follows (2) under the conditions below.
RON = 0.60 Ω (＠1.0 A)
IOUT (Peak: max) = 1.0 A
VM = 24 V
VDD = 5 V
P (out) = 2 (Tr) × 1.0² (A) × 0.60 × 2 (Ω) = 2.40 (W) ........................................(2)
Power consumed by the logic block and IM
The following standard values are used as power dissipation of the logic block and IM at operation.
I (LOGIC) = 2.5 mA (typ.):
I (IM3) = 10.0 mA (typ.): operation/unit
I (IM1) = 2.0 mA (typ.): stop/unit
The logic block is connected to VDD (5 V). IM (total of current consumed by the circuits connected to
VM and current consumed by output switching) is connected to VM (24 V). Power dissipation is
calculated as follows:
P (Logic&IM) = 5 (V) × 0.0025 (A) + 24 (V) × 0.010 (A) = 0.25 (W) ...............(3)
Thus, the total power dissipation (P) is
P = P (out) + P (Logic&IM) = 2.65 (W)
Power dissipation at standby is determined as follows:
P (standby) + P (out) = 24 (V) × 0.002 (A) + 5 (V) × 0.0025 (A) = 0.06 (W)
For thermal design on the board, evaluate by mounting the IC.
15
2005-03-02