ADP1823 Datasheet, PDF (29/32 Pages) Analog Devices – Dual, Interleaved, Step-Down DC-to-DC Controller with Tracking

ADP1823
APPLICATION CIRCUITS
The ADP1823 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 33 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’s OSCON™ capacitors, which have low ESR and high
current ripple rating. An alternative to the OSCON capacitors
IN = 5.5V TO 20V
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. Since 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 33 shows that the
polymer aluminum or the aluminum electrolytic capacitors can
be used at the outputs.
1µF
1.2V, 20A
C_OUT2
820µF ^{1µF 5600pF}
25V
×2
390Ω
C_IN2
180µF
20V
L2
1µH
1µF
D2
0.47µF
M4
2kΩ
M6
M5
2kΩ
120nF
2kΩ
10kΩ
4.7nF
PV IN _EN1
TRK1
EN2
TRK2
VREG
BST1
BST2
DH1
DH2
ADP1823
SW1
CSL1
SW2
CSL2
DL1
DL2
PGND1 PGND2
FB1
FB2
COMP1
COMP2
GND
FREQ
LDOSD
SYNC
D1
0.47µF
CIN1
1µF 180µF
20V
PGND
M1
L1
1µH
2kΩ
M2
M3
2kΩ
10nF 1µF
200Ω
1.8V, 20A
C_OUT1
1200µF
6.3V
×3
1.5nF
1kΩ
47kΩ
6.8nF
AGND
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
Figure 33. Application Circuit with 20 A Output Loads
Rev. A | Page 29 of 32