TEA1204T Philips Semiconductors, TEA1204T Datasheet - Page 11

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

Philips Semiconductors
A typical component choice for an upconverter from
3 NiCd cells or one LiIon cell to 5.0 V in a GSM handset
(peak power 7.5 W, peak current 2.7 A) is:
For lower power applications, the I
the inductor can be scaled back by the scaling factor of the
output current from the values above. The same holds for
the ESR value of the output capacitor. A further
improvement is increase of inductance and decrease of
output capacitance.
An additional circuit to prevent start-up deadlock in
upconversion is shown in Fig.8. The function of TR1, R1
and R2 is to put the converter into shut-down mode when
the input source is suddenly disconnected. The circuit
operates as follows. When V
and the SHDWN pin is kept LOW. As soon as V
1 V, TR1 no longer conducts and the device is put into
shut-down before V
signal is available which indicates the presence of the
input voltage source, this signal should be applied to the
SHDWN pin. TR1, R1 and R2 should be omitted in that
case.
1998 Mar 02
L1; L = 10 H; I
Coilcraft DO3308-103
C1; C = 100 F; low ESR capacitor; necessity depends
on type of input voltage source
C2; C = 330 F; ESR = 0.1 ; e.g. Sprague 595D series
D1; medium power Schottky diode; e.g. Philips
PRLL5819.
High efficiency DC/DC converter
sat
O
>2.3 A; low DC resistance, e.g.
falls below 2 V. In the event that a
I
is present, TR1 conducts
sat
and R
DC
I
values of
falls below
11
More application information can be found in the
associated application note.
handbook, halfpage
Fig.8 External deadlock prevention circuit.
V I
2.7 M
R2
V O
TR1
R1
1 M
SHDWN
Product specification
MGK930
TEA1204T