TPS65530_08 Datasheet, PDF (13/28 Pages) Texas Instruments – FULLY INTEGRATED 8-CHANNEL DC/DC CONVERTER FOR DIGITAL STILL CAMERAS

TPS65530
www.ti.com....................................................................................................................................................... SLVS744C – OCTOBER 2007 – REVISED MAY 2008
PROTECTION
Change
mode
Detect
condition
OCP
Comeback
condition
Change
mode
OVP
Detect
condition
Comeback
condition
Change
mode
TSD
Detect
condition
Comeback
condition
Table 2. Protection Conditions
CH1–CH6
CH7
CH8
REF (LDO)
All CH shutdown (latch-off)
(without power OFF sequence)
All CH shutdown
All CH shutdown (latch-off)
Forced OFF at MOSFET (latch-off) (without power (without power OFF
OFF sequence)
sequence)
Current over the threshold, V_OUT
less than 80% to compare the
target, and
count 64 cycle × 1.5 MHz
Current over the
threshold
V_OUT less than 70% to
compare the target
V_OUT less than 80% to
compare the target
XSLEEP: Change level from Low
to High
ENAFE: Change level from Low
to High (for CH4)
EN56: Change level from Low to
High (for CH5/6)
or
V_CC2: Apply more than UVLO
threshold (1.4 V) after removing
V_CC2
Forced OFF at applicable CH
MOSFET
Current less than the
threshold (automatic
restoration)
or
V_CC2: Apply more than
UVLO threshold (1.4 V)
after removing V_CC2
Forced OFF at
MOSFET, load switch
turns ON
XSLEEP: Change level
from Low to High
ENAFE: Change level
from Low to High
or
V_CC2: Apply more than
UVLO threshold (1.4 V)
after removing V_CC2
XSLEEP: Change level from
Low to High
ENAFE: Change level from
Low to High
or
V_CC2: Apply more than UVLO
threshold (1.4 V) after
removing V_CC2
Forced OFF at MOSFET
Voltage over the threshold at
feedback
Voltage over the
threshold at feedback
Voltage over the
threshold at feedback
No OVP function
Voltage less than the threshold at EN7: Change level from
feedback (auto-recovery)
Low to High
Voltage less than the
threshold at feedback
(auto-recovery)
All CH shutdown (without power OFF sequence)
The junction temperature is more than the threshold.
XSLEEP: Change level from Low to High, ENAFE: Change level from Low to High (for CH4), EN56: Change level from
Low to High (for CH5/6), or V_CC2: More than 1.4 V
CHANNEL DESCRIPTIONS
CH1/3 Description
Both CH1 and CH3 are the same topology. CH1/3 are the voltage-mode-controlled synchronous buck converters
for engine core (CH1) or external memory (CH3). Both high-side and low-side switches are integrated into the
device and consist of NMOS-FET only. The gate of the high-side switch is driven by bootstrap circuit. The
capacitance of the bootstrap is included in the device. These channels are able to operate up to 100% duty
cycle.
This device has a discharge path to use the switch (Q_Discharge1/3) for the CH1/3 output capacitor via the
inductor. The switch is activated after the power OFF sequence has started. Typical resistance at the discharge
circuit is 1 kΩ. When the device detects the threshold at FB1/3 after the power OFF sequence has started, the
MOSFET turns OFF and the output is fixed with high impedance.
It is acceptable to connect the battery to V_CC1/V_CC3 (pins 18/23) directly when the battery voltage is more than
2.5 V. When the battery voltage is less than 2.5 V, the CH8 output should be connected to V_CC1/V_CC3.
The output voltage is programmed from 0.9 V to 2.5 V (both CH1 and CH3) to use the feedback loop sensed by
the external resistances. The output voltage is calculated by Equation 3. The block diagram is shown in Figure 4.
V_OUT = (1 + R2/R1) × 0.6 [V]
(3)
Where:
V_OUT = Output voltage [V]
R1, R2 = Feedback resistance (see Figure 4)
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