User`s guide

Hardware Components
24 M1 System Management Board User’s Guide
Heater/FAN Loads
The board has two loads controlled by the gate drivers from the M1AFS1500-FG484 device: heater and fan.
Figure 2-10. Heater/ Fan Loads.
Note: Set the AG pad in a high current drive mode, which can sink 25 mA.
Heater
A 7.5 Ω wire-wound resistor (R106) is provided on the board. The resistor is a conduction type of heater element that
dissipates heat of up to 11 W. The heater is used to demonstrate the temperature variance on the temperature diode
(Q10) sitting close to it.
Fan
A 3.3 V fan is provided on the board with a tachometer option to measure the speed of the fan. Each revolution creates
two pulses on the tachometer output. The tachometer output signal goes to the A3P250-FG144 device. A connector
JP18 is provided in parallel to the fan load to allow removing the fan and adding an external load.
Note: Do not add a load that requires more than 300 mA.
Voltage Monitors
Three monitors are provided on the board to monitor external voltages: EXT_VOL[1:3]. Voltages of an external board
can be monitored by using alligator clips to plug into one of the monitor pins. The voltage is monitored using the AV
pads of the M1AFS1500-FG484 device. The input voltage (V1) from the external board can be divided down to one of
the options below using a 4-pole switch (Table 2-19). Three switches are provided to allow independent division of the
external voltages: switch U15 is used for EXT_VOL[1}, switch U17 is used for EXT_VOL[2] and switch U18 is used
Table 2-18 · AG Pads Settings
AG Pads (M1AFS1500-FG484) LED
Tristate Off
On-High Current Drive On
VCC
Load
A
G
Q11