Linear Technology LTC4370 Demo Manual

DESCRIPTION
Demonstration circuit DC1741A features the LTC4370, a
two supply diode-OR current sharing controller in a typical
2.9V to 18V, 16A sharing application.
The maximum MOSFET voltage drop V
set with an external resistor, up to 600mV. A fast gate
turn-on reduces the load voltage droop during supply
switchover. If the input supply fails or is shorted, a fast
turn-off minimizes the transient reverse current.
Disabling the load sharing function turns the LTC4370
into a dual ideal diode controller.
Two enable input pins, EN1 and EN2, allow enabling and
disabling each rail's MOSFET individually while the MOS-
FETs' inherent diodes create diode-OR connection when
the MOSFETs are disabled. The LTC4370 provides a rich
PERFORMANCE SUMMARY
SYMBOL PARAMETER
V V and V
IN IN1
V V External Supply Operating Range
CC(EXT) CC
V V Regulated Voltage
CC(REG) CC
V Error Amplifier Input Offset
EA(OS)
g Error Amplifier Gain
m(EA)
V Forward Regulation Voltage (V
FR
ΔV MOSFET Gate Drive (GATE-V
GATE
I GATE1, GATE2 Fast Pull-Up Current
GATE
GATE1, GATE2 Fast Down-Up Current
GATE1, GATE2 Off Pull-Down Current
EN1, EN2 Threshold Voltage
V
EN(TH)
ΔV MOSFET On-Detect Threshold (GATE-V
GATE(ON)
I Maximum Continuous Load Current
OUT
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= V
FR
Input Voltage Operating Range
IN2
– V )
IN OUT
)
IN
)
IN
DEMO MANUAL DC1741A
Two-Supply Diode-OR
Current Balancing Controller
set of features to support shared current diode-ORed ap-
plications including:
• Load Sharing Between Two Supplies
– OUT is
IN
• Elimination of the Need for Active Control of Input
Supplies
• Elimination of "Share Bus"
• Reverse Current Blocking
• Elimination of Shoot-Through Current During Start-Up
or Faults
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 of Linear
Technology Corporation. All other trademarks are the property of their respective owners.
Specifications are at T = 25°C
A
CONDITIONS
With External V Supply
CC
V , V ≤ V
IN1 IN2 CC
V =1.2V, V = 5V
IN CC
V =12V
IN
V = 0.2V; I = 0, –1μA; Highest V
FWD
V = 0.2V; I = 0, –1μA; Highest V
FWD
V = 0.4V, ΔV = 0V, CPO = 17V
FWD GATE
V = –2V, ΔV = 5V,
FWD GATE
Corresponding EN =1V, ΔV
= 2.5V
GATE
EN Falling
FETON Transitions High
Sharing active, limited by SUM85N03 FET Dissipation
MIN TYP
2.9
0
2.9
4.5 5
0
150
2 12
2 25
= 12V 10 12
IN
= 2.9V 4.5 7
IN
–0.9 –1.4
0.9 1.4
65 110
580 600
0.28 0.7
LTC4370
MAX UNITS
18 V
V
CC
6.0 V
5.5 V
±2 mV
μS
25 mV
50 mV
14 V
9 V
–1.9 A
1.9 A
160 μA
620 mV
1.1 V
16.6 A
dc1741af
1