Quick Start Procedure - Linear Technology DC1587 Demo Manual

DEMO MANUAL DC1587

QUICK START PROCEDURE

2. With the power off, connect a low voltage adjustable
power supply and three voltmeters as shown in Figure 1
(ammeters are optional). Switch the power supply on
and adjust the voltage to approximately 450mV, and
move the JP5 jumper to the ON position. With no load
resistor on either output, verify that the BOOST and LDO
output voltages are within the specifi cations shown in
Table 1. Increase the input voltage to 1.5V and connect
suitable load resistors to the output terminals to verify
the output voltages under load. The maximum Boost
output current is dependant on V
LDO output current is 6mA
Maximum power point control (MPPC) prevents the
converter from pulling the input supply voltage down
below a preset voltage level when the maximum input
supply current is reached. The converter does this by
dynamically reducing the converter's output voltage
2
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and the maximum
IN
Figure 1. Proper Measurement Equipment Setup
and current as the input voltage begins to drop due
to the input power source current limitations. Without
MPPC, a converter would pull the input power source
down to near 0V, resulting in near zero output power.
MPPC is especially useful with power sources that have
relatively high or variable source impedances such as
solar cells and other energy harvesting devices. The
following exercise is to illustrate the MPPC function.
To demonstrate the MPPC function, place a 10Ω, 1W
resistor in series with the demo board input terminal
(V ) to simulate a high impedance power source. Move
IN
jumper JP2 (MPPC) to the 2V position and jumpers JP1
and JP3 to the 5V and 3V positions respectively and
connect voltmeters to measure V
With the power supply set to 3.5V, apply voltage to the
input. With an adjustable load on the boost output,
begin increasing the load on the 5V output.
and boost V .
IN OUT
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