Texas Instruments TPS61080/81-147 Evaluation Board TPS61080/81EVM-147 TPS61080EVM-147 TPS61080EVM-147 Hoja De Datos
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TPS61080EVM-147
SLVS644D – FEBRUARY 2006 – REVISED APRIL 2013
IC attempts to start up one time. After 57ms, the IC restarts in a fashion described in the above section. If the
short is cleared, the boost regulator properly starts up and reaches output regulation. However, after reaching
regulation, if another event of short circuit current limit occurs, the IC goes into shutdown mode again, and the
fault can only be cleared by toggling the EN pin or POR. Under a permanent short circuit, the IC shuts down after
a start up failure and waits for POR or the EN pin toggling.
short is cleared, the boost regulator properly starts up and reaches output regulation. However, after reaching
regulation, if another event of short circuit current limit occurs, the IC goes into shutdown mode again, and the
fault can only be cleared by toggling the EN pin or POR. Under a permanent short circuit, the IC shuts down after
a start up failure and waits for POR or the EN pin toggling.
The same circuit also protects the ICs and external components when the SW pin is shorted to ground. These
features provide much more comprehensive and reliable protection than the conventional boost regulator.
features provide much more comprehensive and reliable protection than the conventional boost regulator.
lists the IC protection against the short of each IC pin.
Table 1. TPS61080/1 Short Circuit Protection Mode
SHORTED TO GND
FAULT DETECTION
IC OPERATION
HOW TO CLEAR THE FAULT
IC restarts after 57ms; If it happens again,
L, SW
INDUCTOR > I
SC
for 13
μ
s
Turn off isolation FET
the fault can only be cleared by toggling
EN or POR.
EN or POR.
OUT (during start
OUT <Vin– 1.4V for 2 ms
IC shuts down
Cleared by toggling EN or POR
up)
OUT (after start up)
OUT <Vin– 1.4V without delay
IC shuts down
Cleared by toggling EN or POR
EN
N/A
IC disabled
N/A
FSW
N/A
600 kHz switching frequency
N/A
Disable PWM switching and no output;
SS
N/A
N/A
but still dissipate quiescent current.
FB
N/A
Over voltage protection of the OUT pin OUT voltage fails by OVP hysteresis
GND, PGND, VIN
N/A
N/A
N/A
OVERVOLTAGE PROTECTION
When TPS61080/1 is configured as regulated current output as shown in the TYPICAL APPLICATIONS, the
output voltage can run away if the current load is disconnected. The over voltage condition can also occur if the
FB pin is shorted to the ground. To prevent the SW node and the output capacitor from exceeding the maximum
voltage rating, an over voltage protection circuit turns off the boost regulator as soon as the output voltage
exceeds the OVP threshold. When the output voltage falls 0.7V below the OVP threshold, the regulator resumes
the PWM switching unless the output voltage exceeds the OVP threshold.
output voltage can run away if the current load is disconnected. The over voltage condition can also occur if the
FB pin is shorted to the ground. To prevent the SW node and the output capacitor from exceeding the maximum
voltage rating, an over voltage protection circuit turns off the boost regulator as soon as the output voltage
exceeds the OVP threshold. When the output voltage falls 0.7V below the OVP threshold, the regulator resumes
the PWM switching unless the output voltage exceeds the OVP threshold.
UNDERVOLTAGE LOCKOUT (UVLO)
An undervoltage lockout prevents mis-operation of the device for input voltages below 1.65 V (typical). When the
input voltage is below the undervoltage threshold, the device remains off and both PWM and isolation switch are
turned off, providing isolation between input and output. The undervoltage lockout threshold is set below
minimum operating voltage of 2.5V to avoid any transient VIN dip to trigger UVLO and causes converter reset.
For the VIN voltage between UVLO threshold and 2.5V, the IC still maintains its operation. However, the spec is
not assured.
input voltage is below the undervoltage threshold, the device remains off and both PWM and isolation switch are
turned off, providing isolation between input and output. The undervoltage lockout threshold is set below
minimum operating voltage of 2.5V to avoid any transient VIN dip to trigger UVLO and causes converter reset.
For the VIN voltage between UVLO threshold and 2.5V, the IC still maintains its operation. However, the spec is
not assured.
THERMAL SHUTDOWN
An internal thermal shutdown turns off the isolation and PWM switches when the typical junction temperature of
160°C is exceeded. The IC restarts if the junction temperature drops by 15°C.
160°C is exceeded. The IC restarts if the junction temperature drops by 15°C.
ENABLE
Connecting the EN pin low turns off the power switch immediately, but keeps the isolation FET on. If the EN pin
is logic low for more than 74ms, the IC turns off the isolation FET and enters shutdown mode drawing less than
1
is logic low for more than 74ms, the IC turns off the isolation FET and enters shutdown mode drawing less than
1
μ
A current. The enable input pin has an internal 800k
Ω
pull down resistor to disable the device when the pin is
floating.
Copyright © 2006–2013, Texas Instruments Incorporated
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