MEW1000 Series
Test Configurations
Input Reflected-Ripple Current Test Setup
Input reflected-ripple current is measured with a inductor
Lin (4.7uH) and Cin (220uF, ESR < 1.0[ at 100 kHz) to
simulated source impedance.
Capacitor Cin, offsets possible battery impedance.
Current ripple is measured at the input terminals of the
module, measurement bandwidth is 0-500KHz.
To Oscilloscope
+
Battery
+
Lin
Current
Probe
Maximum Capacitive Load
The MEW1000 series has limitation of maximum
connected capacitance on the output.
The power module may operate in current limiting mode
during start-up, affecting the ramp-up and the startup time.
The maximum capacitance can be found in the data sheet.
Overcurrent Protection
To provide protection in a fault (output overload) condition,
the unit is equipped with internal current limiting circuitry and
can endure current limiting for an unlimited duration. At the
point of current-limit inception, the unit shifts from voltage
control to current control. The unit operates normally once the
output current is brought back into its specified range.
+Vin
+Out
Load
DC / DC
Converter
-Vin
-Out
Cin
Input Source Impedance
The power module should be connected to a low
ac-impedance input source. Highly inductive source
impedances can affect the stability of the power module.
In applications where power is supplied over long lines and
output loading is high, it may be necessary to use a capacitor
on the input to insure startup.
By using a good quality low Equivalent Series Resistance
(ESR < 1.0[ at 100 kHz) capacitor of a 1.5uF for the 24V and
48V devices, capacitor mounted close to the power module
helps ensure stability of the unit.
+
DC Power
Source
-
+
Cin
-Vin
-Out
+Vin
DC / DC
Converter
+Out
Load
Peak-to-Peak Output Noise Measurement Test
Use a Cout 0.47uF ceramic capacitor.
Scope measurement should be made by using a BNC
socket, measurement bandwidth is 0-20 MHz. Position the
load between 50 mm and 75 mm from the DC/DC Converter.
+Vin
Single Output
DC / DC
Converter
-Vin
-Out
+Out
Copper Strip
Cout
Scope
Resistive
Load
+Vin
Dual Output
DC / DC
Converter
-Vin
+Out
Com.
Copper Strip
Cout
Cout
Scope
Resistive
Load
Scope
Output Ripple Reduction
A good quality low ESR capacitor placed as close as
practicable across the load will give the best ripple and noise
performance.
To reduce output ripple, it is recommended that 3.3uF
capacitors are used on output.
+
DC Power
Source
-
-Vin
+Vin
Single Output
DC / DC
Converter
-Out
+Out
-Out
Design & Feature Considerations
Remote On/Off
Negative logic remote on/off turns the module off during a
logic high voltage on the remote on/off pin, and on during a
logic low.
To turn the power module on and off, the user must supply
a switch to control the voltage between the on/off terminal and
the -Vin terminal.
The switch can be an open collector or equivalent.
A logic high is 2.9V to 15V.
A logic low is under 0.6 VDC or open circuit, drops down to
0VDC by 2mV/]
The maximum sink current at on/off terminal during a logic
low is 1 mA.
The maximum allowable leakage current of the switch at
on/off terminal =(under 0.6VDC or open circuit) is 1mA.
Cout
Load
+
DC Power
Source
-
+Vin
+Out
Dual Output
DC / DC
Com.
Converter
Cout
Load
-Vin
-Out
REV:3 2008/10/02
MINMAX
6
MINMAX [ MINMAX TECHNOLOGY CO., LTD. ]
