Linear Technology DC1962C, Демонстрационное руководство

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dc1962cf
DEMO MANUAL DC1962C
Figure 4. Sequencing Output Channels with DC1962C Using TON_DELAY
common Demo BoarD operations
Figure 5. TON_DELAY Configuration Figure 6. TOFF_DELAY Configuration
Sequencing Output Channels
The LTC3880, LTC2974, and LTC2977 have been pre-
configured with different TON_DELAY values for each
channel. The TON_DELAY parameter is applied to each
device relative to the respective CONTROL pin (RUN on
the LTC3880). On this demo board, all CONTROL/RUN
pins are wire OR’d. Therefore the TON and TOFF delays
are enforced relative to one edge. Figure 4 shows an oscil-
loscope screen capture of four output rails sequencing up.
The same applies to TOFF_DELAY values. When the
CONTROL switch is set to the OFF position, all rails will
power down sequentially based on each of the device’s
TOFF_DELAY values. Each channel has an LED which
visually indicates if the channel has power. When the
CONTROL pin is switched on and off, you will observe the
relative on/off timing of the 14 channels. Figures 5 and 6
show TON and TOFF delays for all channels at once. You
will notice in Figure 1 that the GUI shows idealized on/off
waveforms. This graphical view shows the relative TON and
TOFF delays in response to an on/off command, whether
it comes from the CONTROL switch or PMBus command.
Once a new timing value is entered, the timing change will
be reflected in the idealized waveforms.