Datasheet

Software Configuration

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Users can set the enable polarity, however, in two configurations, depending on the desired result for the

supplies during board power up. Table 3 shows the two configurations available for each supply setting.

Mode 1 sets all enable polarities to their appropriate state for turnon. This means that when set in Mode 1,

all supplies begin to turn on in the configured sequence as soon as the board is powered up. When Store

RAM to flash is also pushed when setting in mode 1, the board does not need the USB cable connected

or have the Fusion GUI software running, the sequencing simply occurs when the board is powered up or

when the PWR_RESET SW3 is pushed. Note that when sequencing the supplies, do not turn the board

on using the main switch to sequence because transient voltage spikes result from the main supply

turning on everything for a short time before the UCD90120A takes control. Sequencing from mode 1, the

board powers up in a sequence, then the user can press and hold the SW3 button while all connections

are made to the output, and when the button is released, the power comes on in sequence.

Figure 4. Enable Polarity and Output Mode Type

Table 3. Enable Polarity Modes For Desired Turnon or Turnoff Conditions

Output Supplies Mode 1 – Enable Polarities Mode 2 – Enable Polarities

5 V Active low Active high

3.3 V Active low Active high

1.8 V Active low Active high

ADJ1 Active high Active low

ADJ2 Active high Active low

NEG Active high Active low

Table 3 shows the second mode possible for each supply. Mode 2 sets the supplies to the enable polarity

keeping supplies off when the board powers on. In this mode, the Fusion GUI software and a USB cable

connected to the board are required. When operating in this mode and once all the desired delay settings

are set, a write to the hardware is possible. This write to hardware is in real time and sets all supplies to

the appropriate delays. Once the configuration for turnon is set, then all enable polarities for each supply

TSW2200EVM: Multi-Output Power Supply Evaluation Module SLWU081A–May 2012–Revised December 2012

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