lb11600jv Sanyo Semiconductor Corporation, lb11600jv Datasheet - Page 22

• Manufacturer Part Number: lb11600jv
• Description: Brushless Motor Predriver Ic For Automotive Applications
• Manufacturer: Sanyo Semiconductor Corporation

The time (n times the PWMIN period) required for the potential, which is increased by the V2 potential difference (∆V)
on each input pulse, to exceed the threshold voltage (Vth = 1.25V) is the reset period (Trest).
<PWMRE Reset Time Setting Example>
Since ∆V (0.644) is added on each PWMIN input pulse, and
the threshold voltage (1.25V) will be exceeded on the second pulse.
From the formula for the on time: t1' = CR × ln ((V0 – Ipwmre × R)/(V1 - Ipwmre × R))
Since the potential difference with respect to 1.25V due to the rise potential V2 of the second PWMIN pulse is 1.25 -
0.664 = 0.586V, 1.25V will be exceeded in the on duty state. Therefore,
Thus the reset time Trest will be one PWMIN period plus t1'.
V2 + ∆V + ∆V⋅⋅⋅ ≥ 1.25V
Trest ≤ TPWMIN × n (s)
V CC = 5V, PWMIN = 25kHz, on duty ratio = 20%
PWMRE:
PWMIN = 25kHz = 40µs
t1 = 40µs × 0.2 = 8µs
V1 = (V0 - Ipwmre × R) × e-t1/RC + Ipwmre × R
V2 = V1 × e-t2/RC
V2 + ∆V = 0.664 + 0.664 ≥ 1.25V
t1' = 2200pF × 180kΩ × ln ((0.664 – 200µA × 180kΩ) / (1.25 – 200µA × 180kΩ))
Trest = 40µs + 6.622µs = 46.622µs (s)
= 396µs × ln (35.336/34.75) = 6.622µs (s)
= (0 - 200µA × 180kΩ) × 0.98 + (200µA × 180kΩ)
= - 35.28 + 36 = 0.72 (V)
= 0.72 × 0.922 = 0.664 (V)
C = 2200pF, R = 180kΩ
t2 = 40µs × 0.8 = 32µs
LB11600JV
No.8321-22/30