Linear Technology DC1899A Manual

DESCRIPTION
Demonstration circuit 1899A controls two independent
power rail circuits each with Hot Swap™ and ideal diode
functionality provided by the LTC4228-1/LTC4228-2 dual
ideal diode and Hot Swap controller.
DC1899A facilitates evaluation of LTC4228 performance
in different operation modes such as supply ramp-up,
power supply switchover, steady state, and overcurrent
faults. Power supply switchover mode can be realized as
either an ideal diode or as a prioritizer.
Each DC1899A circuit is assembled to operate with a
12V supply and 9A maximum current load. The main
components of the board are the LTC4228 controller, two
MOSFETs operating as ideal diodes, two MOSFETs operat-
ing as Hot Swap devices, two current sense resistors, two
jumpers for independently enabling each rail, six LEDs to
PERFORMANCE SUMMARY
SYMBOL PARAMETER
V Input Supply Range
IN
V Internal V Undervoltage Lockout
INTVCC(UVL) CC
V Internal V Undervoltage Lockout Hysteresis
INTVCC(HYST) CC
Ideal Diode Control
ΔV Forward Regulation Voltage (V
FWD(REG)
ΔV External N-Channel Gate Drive
DGATE
(V – V )
DGATE IN
I CPO Pull-Up Current
CPO(UP)
I DGATE Fast Pull-Up Current
DGATE(FPU)
I DGATEn Fast Pull-Down Current
DGATE(FPD)
Hot Swap Control
ΔV Circuit Breaker Trip Sense Voltage
SENSE(CB)
+
(V – V
SENSEEn SENSEEn
ΔV Active Current Limit Sense Voltage
SENSE(ACL)
+
(V – V
SENSEEn SENSEEn
I External N-Channel Gate Pull-Up Current
HGATE(UP)
I External N-Channel Gate Pull-Down Current
HGATE(DN)
I External N-Channel Gate Fast Pull-Down Current
HGATE(FPD)
Specifications are at T
CONDITIONS
INTV
– V )
IN OUT
ΔV
IN < 7V
IN = 7V to 18V
CPO = IN = 2.9V
CPO = IN = 18V
ΔV
ΔV
–
)
–
)
Gate Drive On, HGATE = 0V
Gate Drive Off, OUT = 12V, HGATE = OUT + 5V
Fast Turn-Off, OUT = 12V, HGATE = OUT + 5V
DEMO MANUAL DC1899A
LTC4228-1/LTC4228-2
Dual Ideal Diode and
Hot Swap Controller
indicate status, power good and fault conditions separately
for each channel, and input voltage snubbers. There are
pads for optional RC circuits for each Hot Swap MOSFET
gate in order to adjust output voltage slew rate. In addition
to this there are jumpers allowing monitoring of supply
undervoltage conditions at either IN or SENSE+ pins.
The standard configuration (as DC1899A populated by
default) places the ideal diode MOSFET ahead of the Hot
Swap MOSFET. The board also has pads for an alternative
configuration with the Hot Swap MOSFET located ahead
of the ideal diode MOSFET.
Design files for this circuit board are available at
http://www.linear.com/demo
L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks and
Hot Swap is a trademark of Linear Technology Corporation. All other trademarks are the
property of their respective owners.
= 25°C
A
Rising
CC
= 0.1V
FWD
= 0.2V, ΔV = 0V, CPO = 17V
FWD DGATE
= –0.2V, ΔV = 5V
FWD DGATE
MIN TYP MAX UNITS
2.9 18 V
2.1 2.2 2.3 V
30 60 90 mV
10 25 40 mV
5 7 14 V
10 12 14 V
–60 –95 –120 μA
–50 –85 –110 μA
–1.5 A
1.5 A
47.5 50 52.5 mV
55 65 75 mV
–7 –10 –13 μA
150 300 500 μA
100 200 300 mA
dc1899af
1