TEA1204T Philips Semiconductors, TEA1204T Datasheet - Page 6

• Manufacturer Part Number: TEA1204T
• Description: High efficiency DC/DC converter
• Manufacturer: Philips Semiconductors

Philips Semiconductors
Burst mode trigger input
For burst-mode applications, in which the required output
power periodically changes between two different power
levels, the burst mode trigger feature gains optimal
dynamic response. A digital signal indicating the load
change must be connected to the burst pin. Polarity of the
burst signal is arbitrary. When not used, the burst pin must
be tied to pin 3 or pin 6.
Shut-down
When the shut-down pin is made HIGH, the converter
disables both switches and power consumption is reduced
to a few A.
Power switches
The power switches in the IC are one N-type and one
P-type MOSFET, having a typical pin-to-pin resistance of
0.12
current in the switches is 1.0 A.
Temperature protection
At too high device temperature (typical 165 C), the
converter stops operating. It resumes operation when the
device temperature falls below 165 C again. As a result,
low-frequent cycling between on and off state will occur.
It should be noted that in the event of device temperatures
around the cut-off limit, the application differs strongly from
maximum specifications.
Current limiters
If the current in one of the power switches exceeds its limit,
current ramping is stopped immediately, and the next
switching phase is entered. Current limitation is required to
enable optimal use of energy in Lithium-Ion batteries, and
to keep power conversion efficient during temporary high
loads. Furthermore, current limitation protects the IC
against overload conditions, inductor saturation, etc.
1998 Mar 02
High efficiency DC/DC converter
and 0.16
respectively. The maximum average
6
Behaviour at input voltage exceeding the specified
range
In general, an input voltage exceeding the specified range
is not recommended since instability may occur. There are
two exceptions:
handbook, halfpage
Upconversion: at an input voltage equal to or higher than
the target output voltage, but up to 6 V, the converter will
stop switching and the external schottky diode will take
over, resulting in V
drop.
Downconversion: when the input voltage is equal to or
lower than the target output voltage, but higher than
2.6 V, the P-type FET will stay conducting resulting in V
being equal to V
The current limit function remains active.
Fig.3
low power
mode
medium power
mode 1
medium power
mode 2
low DC current
high DC current
Coil current waveforms in the various power
modes.
i
minus some resistive voltage drop.
o
equalling V
i
time
minus the diode voltage
Product specification
TEA1204T
increasing
MGK924
load
o