DC1594A - Demo Manual

DEMO CIRCUIT 1594
LTC4219
QUICK START
GUIDE
LTC4219
5A Integrated Hot Swap Controller
DESCRIPTION
Demonstration circuit DC1594A is a +5V or +12V rail
with hot swap functionality featuring the LTC4219 - 5A
Integrated Hot Swap Controller. As a Controller has two
dedicated voltage versions- for 5.0V and 12V operationthe DC1594 also has similar variation-DC1594A-A (5.0V)
and DC1594A-B ((12V). The DC1594A allows evaluating
performance of the LTC4219 in the transient conditions,
such as turning on and off the power rail, in the steady
state conditions with different load and in the fault conditions, when Controller interrupts its functions from overcurrent, nonproprietary voltage level, or thermal condition.
The LTC4219 features 5% accuracy in 5.4A current limit
and has a current limiting foldback characteristic. Current
limit can be reduced by placing the external resistor be-
tween Iset and GND pins, and it can be adjusted dynamically during transient.
The Controller monitors a load current generating ground
reference signal proportional to the sense resistor voltage. Thermal limit and power good signaling increase
Controller reliability and options in application.
Design files for this circuit board are available. Call
the LTC factory.
L, LTC, LTM, LT, Burst Mode, OPTI-LOOP, Over-The-Top and PolyPhase are registered
trademarks of Linear Technology Corporation. Adaptive Power, C-Load, DirectSense, Easy
Drive, FilterCAD, Hot Swap, LinearView, µModule, Micropower SwitcherCAD, Multimode
Dimming, No Latency ∆Σ, No Latency Delta-Sigma, No RSENSE, Operational Filter, PanelProtect, PowerPath, PowerSOT, SmartStart, SoftSpan, Stage Shedding, SwitcherCAD, ThinSOT,
UltraFast and VLDO are trademarks of Linear Technology Corporation. Other product names
may be trademarks of the companies that manufacture the products.
PERFORMANCE SUMMARY Specifications are at TA = 25°C
SYMBOL
VDD
VDD(UVL)
VOUT(PGTH))
PARAMETER
Input Supply Range
Input Supply Undervoltage Lockout
Output Power Good Threshold
VOUT(PGHYST) Output Power Good Hysteresis
∆VGATE/∆t
RON
ILIM(TH)
GATE Pin Turn-On Ramp Rate
MOSFET+Sense Resistor ON Resistance
Current Limit Threshold
VTIMER(H)
VTIMER(L)
ITIMER(UP)
ITIMER(DN)
ITIMER(RATIO)
TIMER Pin High Threshold
TIMER Pin Low Threshold
TIMER Pin Pull-Up Current
TIMER Pin Pull-Down Current
TIMER Pin Current Ratio
CONDITIONS
VDD Rising
LTC4219-12 Only VOUT Rising
LTC4219-5 Only VOUT Rising
LTC4219-12 Only
LTC4219-5 Only
VFB= 1.23V
VFB= 0V
VFB= 1.23V, RSET= 20kΩ
VTIMER Rising
VTIMER Falling
VTIMER =0
VTIMER =1.2V
ITIMER(DN)/ ITIMER(UP)
MIN
2.9
2.65
10.2
4.2
127
53
0.15
15
5.0
1.0
2.3
1.2
0.1
80
1.4
1.6
TYP
2.73
10.5
4.35
170
71
0.3
33
5.4
1.4
2.7
1.235
0.21
100
2
2
MAX
15
2.85
10.8
4.5
213
89
0.55
50
5.8
1.9
3.2
1.28
0.3
120
2.6
2.7
UNITS
V
V
Vo
V
mV
mV
µA
mΩ
A
A
A
V
V
µA
µA
%
1
LTC4219
OPERATING PRINCIPLES
The LTC4219A-12 and LTC4219A-5 are suited accordingly for 12V and 5V power control in applications for hot
board insertion or removal with electronic circuit breaker
function, foldback current limiting, load current monitoring, power good and fault signaling. The LTC4219A has a
rich set of features to support hot swap applications including:
■
■
■
■
■
■
5% Accurate Current Limit for 5.4A,,
Adjustable Current Limit for lower than 5.4A,
Adjustable Inrush Current Control,
Load Current Monitoring,
Adjustable duration for Current Limit before switch is
turned off,
Power good and Fault signaling.
QUICK START PROCEDURE
The Demo Board DC1594A includes the LTC4219-12 or
LTC4219-5 5A Integrated Hot Swap Controller, four LEDs
to indicate input and output voltages (D2, D4), and the
state of the fault (D3) and Power Good (D5) pins, three
jumpers, and a few associated components.
Demonstration circuit DC1594A is easy to set up to
evaluate the performance of the LTC4219. Refer to Error!
Reference source not found. for proper measurement
equipment setup and follow the procedure below:
load. For LTC4219-12 this time must be in the range
(22.0-80.0) ms, and for LTC4219-5 - (9.0-34) ms.
5.
Connect a Low Capacitive Load (5600uf for both
Controllers-LTC4219-12 and LTC4219-5) to the output of hot swap circuitry (OUT turret). Turn on the
controller. This power up should be successful and
two LEDs (OUT –green- and PG -orange) lights must
indicate this.
6.
Connect a High Reset Capacitive Load (6800uf for
both Controllers-LTC4219-12 and LTC4219-5) to the
output of hot swap circuitry. Turn on a controller.
This power up should be unsuccessful, and no light
of the two LEDs, - OUT and PG,- and the light of the
FLT LED (red) confirms this. Reset controller after a
fault.
7.
Load the output with a Low Resistive Load (2.5
Ohms for LTC4219-12 and 1.1 Ohms for LTC42195) and turn the controller on. Controller should successfully keep this load. Verify performance of the
current monitoring.
8.
Load the output with a High Resistive Load (2.0
Ohms for LTC4219-12 and 0.8 Ohms for LTC42195) and turn the controller on. Controller should fail to
keep this load. Reset Controller after a fault.
9.
Pay special attention to the MOSFET Safe operating Area, when TIMER period is changed.
The performance evaluation for LTC4219-12 and
LTC4219-5 is identical. The difference is in a value of the
loading components and power supply voltage.
1.
Place jumpers in the following positions:
JP1 CT
OFF,
JP2 EN1
DISABLE,
JP3 EN2
ENABLE.
2.
With power off, connect the power supply terminals to the VDD (E1) and GND (E3) turrets.
3.
In all evaluations steps the Demo Board is connected to the appropriative power supply (+12V or
+5.0V), Controller is turned on by replacing the
jumper head JP2 position from the DISABLE to the
ENABLE, and a resetting Controller is achieved by
first placing the jumper head JP2 on the DISABLE
position and then on the ENABLE.
4.
2
Place a scope probe to the output turret, turn on
the Controller, and measure a power-up time with no
LTC4219
Figure 1. Proper Equipment Measurement Set-Up
3
LTC4219
4
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