Theory of Operation
Vibrex 2000 and Vibrex 2000 Plus User Guide 121
6.2.4 Power Subsystem
The Vibrex unit’s power subsystem has the following components:
• Battery power
• On-off logic
• Power supply, 12 Vdc (including photocell power)
• Power supply, 5 Vdc
• Power supply, -12 Vdc
• Short-circuit protection circuitry
6.2.4.1 Battery Power
The Vibrex unit operates with four D-size batteries, nominally 1.5 Vdc
each. This setup provides an input range of 3.5 to 6.4 Vdc. The user can
use rechargeable batteries, but they do not provide so long an operating
time nor the low-power warning time that the recommended alkaline
batteries are able to give.
The batteries are always powering a very low-power on-off logic circuit.
This circuit uses an input from the keyboard (
ON/OFF
key) to turn on the
main 12V supply. The off-current drain on the batteries is less than 50 µa.
The microprocessor can switch the on-off logic off (Auto-off feature) to
save power.
For more information on using batteries with the Vibrex unit, see
Section 6.3.1 “Batteries and Replacement” on page 123.
6.2.4.2 On-Off Logic
Once the on-off logic senses a press of the
ON/OFF
key, it powers up the
battery-driven 12V power supply. This supply, in turn, powers two
additional supplies, 5Vand -12V.
6.2.4.3 Power Supplies
All power supplies reside on the main PCB. There are three, as explained
in this section.
Power Supply, 12V -
The 12V supply powers the other supplies, the
Velocimeter sensors and, through a microprocessor-controlled power
switch, the photocell probe.
To Next Page
Loading...
Need help?
General
