DC1046A - Demo Manual

QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 1046A
HIGH EFFICIENCY 48V BUCK BOOST DC/DC SUPPLY
LTC3780EG/LTC4440ES6
DESCRIPTION
Demonstration circuit 1046A is a non-isolated, high
efficiency buck-boost DC/DC supply featuring
LTC®3780EG and LTC®4440ES6. The LTC3780 is a
high performance 4-switch synchronous buck boost
regulator and the LTC4440 is a 100V-rated FET
driver. The input voltage of the demo board is designed for 36V to 72V. The output voltage is 48V. At
25C° room temperature, the maximum output current is 5A without a cooling fan and 6A with 150LFM
air flow for cooling. An optional 12V bias flyback
supply using the LTC3803 is stuffed on the board to
power the LTC3780 and LTC4440.
Design files for this circuit board are available.
Call the LTC factory.
, LTC and LT are registered trademarks of Linear Technology Corporation.
Table 1. Performance Summary (TA = 25°C)
PARAMETER
CONDITION
VALUE
Input Voltage
Min / Max
36V-72V
Output Voltage VOUT
IOUT = 0A to 6A
48V ± 2%
VIN = 36V to 72V, no fan, at room TA=25C°
5A
VIN = 36V to 72V, 150LFM air flow, at room TA=25C°
6A
36V to 72V input, typical
300kHz
VIN = 36V, VOUT = 48V, IOUT = 6A
96.8% Typical
VIN = 48V, VOUT = 48V, IOUT = 6A
96.6 % Typical
VIN = 72V, VOUT = 48V, IOUT = 6A
96.4 % Typical
Maximum Output Current
Switching frequency
Full Load Efficiency
QUICK START PROCEDURE
Demonstration circuit 1046A is easy to set up to
evaluate the performance of the LTC3780EG. Refer
to Figure 1 for proper measurement equipment
setup and follow the procedure below:
lead on the oscilloscope probe. Measure the input
or output voltage ripple by touching the probe tip
directly across the Vin or Vout and GND terminals.
See Figure 2 for proper scope probe technique.
NOTE: When measuring the input or output voltage
ripple, care must be taken to avoid a long ground
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QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 1046A
HIGH EFFICIENCY 48V BUCK BOOST DC/DC SUPPLY
1.
2.
With power off, connect the input power supply to
VIN and GND. Connect the load between VOUT, and
GND. Preset the load current at 0A (minimum). Refer to Figure 1 for correct test set up. The default
position of FCB jumper JP1 is CCM.
Turn on the input power.
NOTE: Make
ceed 72V.
sure that the input voltage does not ex-
3.
Check for the proper output voltage in the range of
47.0V to 49.0V. If there is no output, temporarily
disconnect the load to make sure that the load is
not set too high.
4.
Once the proper output voltages are established,
adjust the loads within the operating range and observe the output voltage regulation, ripple voltage,
efficiency and other parameters.
Figure 1. Proper Measurement Equipment Setup
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QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 1046A
HIGH EFFICIENCY 48V BUCK BOOST DC/DC SUPPLY
Figure 2. Measuring Input or Output Ripple
LTC3780_LTC4440: Efficiency vs. Load Current
100%
98%
96%
94%
Efficiency (%)
92%
Vin=36V
90%
Vin=48V
88%
Vin=72V
86%
84%
82%
80%
78%
76%
74%
0
1
2
3
4
5
6
Load Current (A)
Figure 3. Typical Supply Efficiency vs Load Current at 36V, 48V and 72V input
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QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 1046A
HIGH EFFICIENCY 48V BUCK BOOST DC/DC SUPPLY
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QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 1046A
HIGH EFFICIENCY 48V BUCK BOOST DC/DC SUPPLY
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