B2000 Power Budget By Dave Haynie A2000/B2000 Power Supply: All of the specifications herein are suggested. When it comes right down to it, the machine is being powered by a well-defined supply, the specifications of which will follow. If you're careful not to exceed the suggested load for any port, you'll be able to fully load every port. However, some of the internal ports can supply more than the suggested amount; for example, an 8 megabyte expansion memory card for the 100 pin bus may draw more than the suggested 2.0 Amps at +5VDC. The connector is capable of supplying more without damage, but the extra current must be carefully worked into a system power budget. Any hardware add-on device that draws more than the suggested amount must state this clearly, as budgeting will be required. Some external ports are current limited, thus the numbers for these ports are representative of the true maximum available. VOLTAGE SYSTEMWIDE LIMIT DESCRIPTION +5 VDC 20.0 Amps Main +5 Voltage supply +5 USER 0.5 Amps Protected +5 for externals -5 VDC 0.3 Amps Negative 5 Volt supply +12 VDC 8.0 Amps Main +12 Voltage supply +12 USER --------- Protected +12 for externals, derived from main +12 -12 VDC 0.3 Amps Main -12 Voltage supply -12 USER --------- Protected -12 for externals, derived from main -12 CONSUMPTION: Everybody wants power. Here's what can be taken, based on your particular setup; you get what's left over: MAIN SYSTEM: +5VDC -5VDC +5USER +12VDC -12VDC Motherboard 2.5A --- --- 50mA 50mA Internal 3-1/2" Floppy [1] 250mA --- --- 350mA --- Internal 5-1/4" Floppy [2] 500mA --- --- 500mA --- Internal 3-1/2" Hard Disk [2] 750mA --- --- 1.0A --- Internal 5-1/4" Hard Disk [2] 1.0A --- --- 1.5A --- EXTERNAL PORTS: Video Port --- 10mA 100mA 100mA --- Floppy Port [1] 250mA --- --- 350mA --- Parallel Port [3] --- --- 10mA --- --- Serial Port --- --- --- 25mA 25mA Keyboard Port [4] 250mA --- --- --- --- Mouse Port [5] --- --- 50mA --- --- INTERNAL SLOTS: CoProcessor Slot [6] 2.0A 40mA --- 40mA 35mA Expansion Slot [6] 2.0A 40mA --- 40mA 35mA Extra PC Bus Slots [7] 0.5A 10mA --- 40mA 15mA Video Slot [8] 1.0A 40mA --- 40mA --- NOTES: [1] Expected typical consumption. This is very device dependent; consult the manufacturer's specification for particular floppy disks. The starting current is expected to be around 400mA for +12V. [2] Expected typical consumption. This is very device dependent; consult the manufacturer's specification for particular disks. Starting current on the +12V supply for most disk drives can be as much as twice the operating current. [3] 47 Ohm Series Resistor limits current. [4] Expected typical consumption. Current from this port is limited. [5] Each port. [6] Each slot. The physical connection can handle 4 Amps; if a 4 Amp device is used in one slot, other slots cannot supply 2.5 Amps each, of course; this requires a total system power budget to be constructed. [7] Shared PC expansion slots should be considered part of the 100 pin connector that they share. If the 100 pin connector is unused, the power suggested for that connector can be used instead by the PC bus. The connectors, like all expansion connectors, are capable of delievering 4 Amps if proper whole-system budgeting is done. The specification here is for both of the non-overlapping PC slots taken together. [8] Like expansion slots, the video slot is capable of supplying 4 Amps. If a 4 Amp device is used, it must be worked into the total system power budget.