TPS53114 Datasheet, PDF (8/20 Pages) Texas Instruments – SINGLE SYNCHRONOUS STEP-DOWN CONTROLLER FOR LOW VOLTAGE POWER RAILS

TPS53114
SLVS887 – APRIL 2009 ..................................................................................................................................................................................................... www.ti.com
I_ocp
= V_trip
R_DS(on)
+ I_L1(ripple)
2=
V_trip
R_DS(on)
+
2
´
1
L1 ´ ¦_sw
´ ^{(VIN - VO) ´ VO}
V_IN
(2)
In an over current condition, the current to the load exceeds the current to the output capacitor; thus, the output
voltage tends to fall off. Eventually, it will cross the under voltage protection threshold and shutdown.
OVER/UNDER VOLTAGE PROTECTION
The TPS53114 monitors a resistor divided feedback voltage to detect over and under voltages. When the
feedback voltage becomes higher than 115% of the target voltage, the OVP comparator output goes high and
the circuit latches the high-side MOSFET driver turns off and the low-side MOSFET driver turns on.
When the feedback voltage becomes lower than 70% of the target voltage, the UVP comparator output goes
high and an internal UVP delay counter begins. After 30us, the TPS53114 latches off both top and bottom
MOSFET drivers. This function is enabled approximately 2.0ms after power-on. The latch off is reset when EN
pin goes low.
UVLO PROTECTION
The TPS53114 has under voltage lock out protection (UVLO) that monitors the voltage of V5FILT pin. When the
V5FILT voltage is lower than UVLO threshold voltage, the device is shut off. The UVLO protection is a non-latch
protection.
THERMAL SHUTDOWN
If the temperature exceeds the threshold value (typically 150°C), the drivers will be shut off both DRVH and
DRVL are set low, the output discharge function is enabled and the device is shut off. Thermal shutdown is a
non-latch protection.
600
f = 350 kHz
500 ^{VO = 1.05 V}
TYPICAL CHARACTERISTICS
45
40 ^{VREG5 = ON}
35
FSEL = V5FILT
400
30
FSEL = GND
25
300
20
200
15
10
100
5
0
−50
0
50
100
150
TJ − Junction Temperature − °C
G001
Figure 1. VIN SUPPLY CURRENT vs. JUNCTION
TEMPERATURE
0
−50
0
50
100
150
TJ − Junction Temperature − °C
G002
Figure 2. VIN SHUTDOWN CURRENT vs. JUNCTION
TEMPERATURE
8
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