Datasheet

ADP1829 Data Sheet
Rev. C | Page 26 of 28
APPLICATION CIRCUITS
The ADP1829 controller can be configured to regulate outputs
with loads of more than 20 A if the power components, such as
the inductor, MOSFETs and the bulk capacitors, are chosen
carefully to meet the power requirement. The maximum load
and power dissipation are limited by the powertrain components.
Figure 1 shows a typical application circuit that can drive an
output load of 8 A.
Figure 34 shows an application circuit that can drive 20 A loads.
Note that two low-side MOSFETs are needed to deliver the 20 A
load. The bulk input and output capacitors used in this example
are Sanyo OSCON™ capacitors, which have low ESR and high
current ripple rating. An alternative to the OSCON capacitors
are the polymer aluminum capacitors that are available from
other manufacturers such as United Chemi-con. Aluminum
electrolytic capacitors, such as Rubycon’s ZLG low ESR series,
can also be paralleled up at the input or output to meet the
ripple current requirement. Because the aluminum electrolytic
capacitors have higher ESR and much larger variation in
capacitance over the operating temperature range, a larger bulk
input and output capacitance is needed to reduce the effective
ESR and suppress the current ripple. Figure 34 shows that the
polymer aluminum or the aluminum electrolytic capacitors can
be used at the outputs.
f
OSC
= 300kHz
M1, M4: IRLR7807Z
L1, L2: TOKO, FDA1254-1ROM
C
OUT1
: SANYO, 2R5SEPC820M
D1, D2: VISHAY, BAT54
M2, M3, M5, M6: IRFR3709Z
C
IN1
, C
IN2
: SANYO, 20SP180M
C
OUT2
: RUBYCON, 6.3ZLG1200M10×16
1µF
C
OUT2
820µF
25V
×2
47kΩ
6.8nF
1.5nF
120nF
10kΩ
4.7nF
1µF
C
OUT1
1200µF
6.3V
×3
10nF
200Ω
2kΩ
M2
2kΩ
1kΩ
390Ω
2kΩ
M5
5600pF
1.2V, 20A
L2
1µH
L1
1µH
M4
M1
0.47µF
0.47µF
1µF
C
IN1
180µF
20V
1µF
C
IN2
180µF
20V
D1
D2
1µF
V
IN
= 5.5V TO 18V
1.8V, 20A
PV IN
TRK1
TRK2
VREG
BST1
DH1
SW1
CSL1
DL1
PGND1
FB1
COMP1
EN1
EN2
BST2
DH2
SW2
CSL2
DL2
PGND2
FB2
COMP2
FREQ
LDOSD
SYNC
GND
AGND
PGND
ADP1829
2kΩ
2kΩ
M6
M3
06784-033
Figure 34. Application Circuit with 20 A Output Loads