TC78B002FNG
2013-10-17
22
12. Current Limit
This function operates when the output voltage reaches the current limit detection voltage (V
RS
= 0.3 V (typ)).
It is detected by the resistor R
F
.
When R
F
=0.51
Ω
, I
OUT
=0.3V (typ)/0.51
Ω
=588mA
During the current limit operation, the operation mode is moved to PWM OFF state by turning off the upper
output power transistor. The operation resumes at the next PWM ON timing.
Masking time is configured to avoid malfunction by noise.
(In case HP = L and HM = H)
Current value which over current
protection operates (I
OUT
)
=
Over current detection voltage (V
RS
)
Detection resistance (R
F
)
RS
端子
電圧
電流リミット
検出期間
2us
OUT1
OUT2
内部
PWM
0.3V (typ)
OFF
（
Hi-Z)
OFF
（
Hi-Z)
OFF
（
Hi-Z)
OFF
（
Hi-Z)
1.5
μ
s
Voltage of
RS pin
Detection
term of
current limit
Internal
PWM
M
OUT1
OUT2
VM
RS
R
F
I
OUT
0.3V
