Power supply connections of a target board
UM2243
22/41
UM2243 Rev 2
8.3
Power supply connections of a target board with basic
connector CN14
CN14 is a common XH series 4-pin connector with a 2.54 mm pitch. It can be used to supply
and measure the target board consumption using a wire connection.
Figure 15. Basic connector CN14
06Y9
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Table 4. Pin description of the basic connector CN14
CN14 pin
Signal
Usage
Pin 1
GND
(-)
Ground of the target
Pin 2
VDD
Alternate power supply source (not measured)
Pin 3
VOUT
(+)
Positive connection of the target, current is measured
Pin 4
VOUT_MONITORING
Mirror of VOUT. Allows VOUT monitoring without impacting
current/power measurements
The target board should be supplied through GND (pin1) and VOUT (pin3) of CN14.
VOUT_MONITORING (pin4) is a buffered copy of the output voltage VOUT. It can be used
to monitor VOUT with a voltmeter or oscilloscope without impacting the current/power
measurements.
Alternatively, VOUT_MONITORING can be used as a reference with a voltage divider to
generate a bias voltage without impacting the current consumption.
Note:
VOUT_MONITORING output has 150 ohms serial resistance to protect it output buffer.
VDD (pin2) can be used as an alternate power source to supply some peripherals of the
target board. The VDD voltage is equal to VOUT (with no load on VOUT). VDD is slightly
higher (30 mV maximum in dynamic mode and 60 mV maximum in static mode) than VOUT
when VOUT is fully loaded. The VDD output current should not exceed 500 mA.
Caution:
When the X-NUCLEO-LPM01A is supplied from a PC (USB host port), and VDD supplies
the target board peripherals, do not exceed the 500 mA total budget allowed by the USB
port.
See also
Figure 2: Hardware block diagram
for further details.
