Power On Troubleshooting - LG -E960 Service Manual

4.22 Power ON Troubleshooting

The main power source of LGE960 is provided by PM8921.
Power ON sequence of LGE960 is,
PWR key press -> PHONE_ON_KEY_N go to low (D7004) -> PM8921 Power Up -> VREG_S1_1P225 (C23027) -> VREG_
L24_1P05 (C23041) -> VREG_S3_1P05 (C23029) -> VREG_S4_1P8 (C23030) VREG_L25_1P225 (C23040), VREG_L1_1P05
(C23061) -> VREG_L4_1P8 (C23058)-> VREG_L6_3P0, VREG_L7_2P95 (C23055)->VREG_L3_3P075 (C23059),VREG_L5_2P95
(C23057) ->VREG_XO (C23034)-> SLEEP_CLK0(R23006),-> XO_OUT_D0 (TP23001) ->PM8921_PON_RESET_N (R21029) ,
APQ_PS_HOLD(R23013) goes to high
BAT_FET_N(IN)
BAT_FET_N(out)
Group 7 regulators
(S1,L24)
Group 6 regulators
(K3,MPP5,GPIO40)
Group 5 regulators
(S4,GPIO41)
Group 4 regulators
(L25,L1)
Group 3 regulators
(None)
Group 2 regulators
(L4)
Group 1 regulators
(L6,L7)
Group 0 regulators
(L3,L5)
VREG_XO
SLEEP_CLK0
XO_OUT_D0
PON_RESET_N
(out)
PS_HOLD (in)
Operating state
LGE Internal Use Only
Must stay low least until PS HOLD is
driven high by the Modem IC
Which regufators are Inciuded in the power-on
sequence is determined by the OPT[3:1] inputs
t(settie)
t(reg1)
t(reg)
Each group can indude as four regulators
(SMPS, LDO, or extemal curcuit)
Whitchin a group - after the rst regulator setties
the next begins turn-on after 4 sleep clock
cycies
t(xo)
t(reset1)
OFF
Power-on sequence
PM8058 Power on sequence
t(reg)
t(pshold)
ON
- 164 - Copyright © 2012 LG Electronics. Inc. All right reserved.
4. TROUBLE SHOOTING
level = do not care for power-o
t(reg0)
Whithin a group -
all regs turn-o at
the same time
t(reg0)
t(reset0)
Other regulators are enabled by
SW anytime during the ON state
OFF
Power-on sequence
Only for training and service purposes