Linear Technology LTC3880 Demo Manual

System Employing LTC3880/LTC2974/LTC2977
Description
The DC1962C is a demonstration system that showcases three
different Linear Technology devices—the
and LTC2977. The LTC2974 and LTC2977 devices are I
SMBus/PMBus power system managers with EEPROM. The
LTC3880 is a dual output PolyPhase
ler with digital power system management. The LTC3880 moni-
tors and controls 2 power supply rails, the LTC2974 monitors
and controls 4 power supply rails, and the LTC2977 monitors
and controls 8 power supply rails. The DC1962C demonstrates
the ability of these devices to sequence, trim, margin, supervise,
monitor, and log faults for fourteen power supplies. Each power
supply channel's output voltage is monitored and each device
monitors its own internal die temperature. Six channels have
current and external temperature sensing.
The DC1962C is a single circuit board that contains fourteen
independent power supply rails. The board employs twelve
LTC3405A 300mA switch-mode regulators, which are config-
ured to be controlled by the LTC2974 (4) and LTC2977 (8). The
LTC3880's two channels have much of the switching regulator
integrated, only requiring the external power stage (power
MOSFETs), inductor, and other passives. This board provides
a sophisticated fourteen channel digitally programmable power
supply system. The rail voltages are programmable within the
trim range shown in Table 1.
This demonstration system is supported by the LTpowerPlay™
graphical user interface (GUI) enabling complete control of the
features on all three devices. Together, the LTpowerPlay software
and DC1962C hardware system create a powerful development
environment for designing and testing configuration settings
of the LTC3880, LTC2974, and LTC2977. These settings can
be stored in each of the devices' internal EEPROM or in a file.
This file can later be used to order pre-programmed devices or
to program devices in a production environment. The software
displays all of the configuration settings and real time measure-
ments from the three digital power ICs. Telemetry allows easy
access and decoding of the fault log created by each device.
The board comes pre-programmed with the EEPROM values
appropriate for the fourteen power supply rails on the DC1962C.
Just plug and play!
Multiple DC1962C boards can be cascaded together to form a
high channel count power supply (see the Multi-Board Arrays
section). This allows for the formation of a single, coherent
Power System Managers with EEPROM
LTC 3880, LTC2974,
®
2
C/
step-down DC/DC control-
®
DEMO MANUAL DC1962C
14-Channel Power Supply
power supply system. The user configures up to eight DC1962C
boards, thereby controlling up to 112 separate power supply
rails. This cascaded configuration demonstrates features of the
LT power system management ICs which enable timing and
fault information to be shared across multiple ICs.
The DC1962C demo board can be powered by an external power
supply, such as a +12VDC supply. Communication with the
software is provided through the DC1613 USB-to-I
PMBus Controller. The following is a checklist of items which
can be obtained from the LTC website or LTC Field Sales.
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• USB-to-I C/SMBus/PMBus Controller (DC1613)
• LTpowerPlay Software
DC1962C Features
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• I C/SMBus Serial Interface
• PMBus Compliant Command Set
• Configuration EEPROM with CRC
• Black Box Fault Logging to Internal EEPROM
• Differential Input, 16-Bit Δ∑ ADC with less than ±0.25% of
Total Unadjusted Error (±0.5% for LTC3880)
• Voltage Servos Precisely Adjust Supply Voltages
• LTC2974 and LTC2977 Utilize 10-Bit trim DACs with
Soft-Connect
• Telemetry Reads Back V
IN
and Ext.)
• Output Sequencer - Time Based or Tracking (Tracking support
on LTC2974 Only)
• Supports Multichannel Fault Management
• Operates Autonomously without Additional SW
• Powered from 6V to 14V
• Packaging:
– LTC2974/LTC2977 in 64-lead QFN
– LTC3880 in 40-lead QFN
Design files for this circuit board are available at
http://www.linear.com/demo
L, LT, LTC, LTM, Linear Technology, the Linear logo and PolyPhase are registered trademarks
and LTpowerPlay is a trademark of Linear Technology Corporation. All other trademarks are the
property of their respective owners.
2
C/SMBus/
, I , V , I , Temperature (Int.
IN OUT OUT
dc1962cf
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