LG KE970 Service Manual page 43

3. TECHNICAL BRIEF
Initial t
> 200 s
0
ENM1 and ENM2
t
SOFT-START
32/32
I or I
M_ F_
SHDN
Setting the Main Output Current
SETM controls M1-M6 regulation current. Current flowing into M1, M2, M3, M4, M5, and M6 is a
multiple of the current flowing out of SETM.
I =I =I =I =I =I
M1 M2 M3 M4 M5 M6
where K = 230, R
SETM
where K = 23, 69, or 230 (depending upon the state of ENM1 and ENM2, see Table 8), and R
the resistor connected between SETM and GND (see the Typical Operating Circuit).
Table 8. ENM1/ENM2 current setting table
ENM1/ENM2 STATES
ENM1 = low, ENM2 = low
ENM1 = low, ENM2 = high
ENM1 = high, ENM2 = low
ENM1 = high, ENM2 = high
Setting the Flash Output Current
SETF controls the F1-F2 regulation current. Current flowing into F1 and F2 is a multiple of the
current flowing out of SETF.
I =I = N * (0.6V / R
F1 F2
where N = 1380, R
HI
1 2 3 4
31/32
30/32
29/32
28/32
Figure 16 Seiral pulse dimming timing diagram
= K * (0.6V / R ) = 18.4mA
SETM
= 7500
BRIGHTNESS
1/10 Brightness
3/10 Brightness
Full Brightness
) = 162mA
SETF
= 5100
SETF
5 27 28 29
t
t
HI
LO
500ns to 250us > 500ns
27/32
5/32
4/32
Shutdown
- 44 -
30 31 32
t
SHDN
2ms (typ.)
32/32
31/32
3/32
2/32
1/32
M1 - M6 CURRENT
0
23 x I
SETM
69 x I
SETM
230 x I
SETM
SHDN
is
SETM