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Linear LTC2937 Manual

Programmable six channel sequencer and voltage supervisor with eeprom
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Description
Demonstration circuit 2313A showcases the LTC2937, a
programmable six channel power supply sequencer and
voltage supervisor.
The LTC2937 provides flexible sequence control for up
to six power supplies. It enables and disables the sup-
plies with configurable sequence order and time delays,
monitors the supplies for power-up and power-down time,
and for overvoltage and undervoltage. It cooperates with
other LTC2937 parts in the system to coordinate power
sequencing activities. It provides flexible fault response to
autonomously supervise the power supplies, and powerful
debug tools to diagnose any problem that causes a power-
supply fault. It holds configuration in non-volatile EEPROM
for completely automatic power system supervision.
The DC2313A board demonstrates the powerful features
of the LTC2937 using six onboard LDO voltage regula-
tors, or by controlling an optional, externally-powered
performance summary
PARAMETER
V
Voltage Range
IN
I
Current to the Board
IN
I
Current
IN
V1-V6 Voltage Range
EN1-EN6 Voltage Range
Regulated LDO Voltage Tolerance
Rated Output Current *V_OUT pins
Board Operating Temperature
Serial Clock Frequency
†
NOTE: Analog switches U7, U8, and U9 (LTC222) are powered by 5V, and limit the maximum voltage range allowed at their S and D pins. The LTC2937
can tolerate up to 16.5V on its ENn pins.
DEMO MANUAL DC2313A
Six Channel Sequencer and
Voltage Supervisor with EEPROM
DC1361 board (an 8-channel power supply board). Multiple
DC2313A boards can also share timing and sequencing
signals to supervise more than six regulated supplies in
a coordinated manner.
The DC2313A connects to a PC through the DC1613 USB-
2
to-I
C/SMBus/PMBus Controller. This connection enables
the LTpowerPlay™ software, to have complete control over
the LTC2937 through the convenient LTpowerPlay GUI.
The GUI allows control over all of the LTC2937 registers,
and visibility into the status of the part in real time, and
it works with Linear Technology demo boards as well as
custom boards with an I
Design files for this circuit board are available at
http://www.linear.com/demo/DC2313A
L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks and
LTpowerPlay is a trademark of Linear Technology Corporation. All other trademarks are the
property of their respective owners.
CONDITIONS
All
Sequenced-Down
Sequenced-Up, No Loads
Volts at the Turret
†
Volts at the Turret
Load Current < 20mA
Load Current Per Channel
Powered
2
I
C Bus Operating
Programmable
2
C interface.
MIN
TYP
MAX
6
12
14
3.8
17.5
0
6
0
6
–1
1
20
0
60
10
400
UNITS
V
mA
mA
V
V
%
mA
°C
kHz
dc2313af
1

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Summary of Contents for Linear LTC2937

  • Page 1 C Bus Operating † NOTE: Analog switches U7, U8, and U9 (LTC222) are powered by 5V, and limit the maximum voltage range allowed at their S and D pins. The LTC2937 can tolerate up to 16.5V on its ENn pins.

  • Page 2: How To Use This Document

    The demo board and the LTpowerPlay software. Each exercise user is referred to the LTC2937 data sheet, and to additional introduces one or two key features of the part, as well as exercises in the DC2313A Advanced User Guide document.
  • Page 3 CONFIgURATION turrets on the board, and basic control over the part by A key feature of the LTC2937 is its non-volatile memory (EE- jumpers and pushbuttons. Connectors can attach to ex- PROM), and its ability to power-up in the correct configuration ternal devices for system prototyping.
  • Page 4 The PB_EN and GLOBAL_ON LEDs will illuminate. will function autonomously without external software, The ENn LEDs will illuminate in sequence: 1-6. which is one of the important capabilities of the LTC2937. The CHn LEDs will illuminate in sequence with the SEqUENCINg UP ENn LEDs.
  • Page 5 EN4 line to GND, while in the sequenced-up state. This The FAULT LED will remain off. will briefly disable and bring down the associated LDO and create a UV condition. The LTC2937 will recognize the low The ALERT LED will remain off. voltage and signal a SUPERVISOR fault.
  • Page 6 All of the LDO regulated supplies turn off. Illuminated up or sequencing-up. CHn LEDs turn off. The LTC2937 is configured to re-try after the fault; it will The LTC2937 is configured to automatically re-try attempt to sequence-up again. There is a rich suite of fault...
  • Page 7 The FAULT LED will remain off. a fault. The MARGIN switch on the DC2313A board pulls down the MARGB pin on the LTC2937, causing it to ignore The ALERT LED will remain off. OV and UV faults while in the sequenced-up state. Note No voltage (UV and OV) limits are measured.
  • Page 8 Linear Technology devices identified on the I C bus. For a single LTC2937 device, the tree is Update register contents by clicking or typing to change small, but if other supported devices are present on the the desired registers, then selecting the “Write All”...
  • Page 9 DEMO MANUAL DC2313A software controL with LtpowerpLay Figure 5. lTpowerPlay gUI window Note that programming the registers in the LTC2937 should lTpowerPlay Telemetry generally be done while the part is in the sequenced-down state. Most of the registers have immediate control over...
  • Page 10 STORE (0x2D) command. RESTORE wipes-out the content of the RAM and replaces it with the EEPROM contents. Only perform a RESTORE when the LTC2937 is in the sequenced-down state, as the RAM operating memory immediately affects the chip, and changing its contents while sequenced-up can result in unpredictable behavior.

  • Page 11: On/Off Control

    ASEL3 = HI ON/OFF CONTROl The LTC2937 provides control over all of its functions through the register interface. This includes ON/OFF con- trol. The part can respond to the hardware ON/OFF pin, or to a register ON/OFF bit, or to both. In this exercise, we...
  • Page 12 Sequenced supplies can be commanded to come-up in any order, and to go down in any (different) order. The LTC2937 provides The ENn LEDs will turn off in sequence: 6-1. up to 1023 ordered sequence positions in which events can be scheduled during sequence-up and sequence-down.
  • Page 13 Remember that we are programmed to ignore the After modifying a register hit F12 on the keyboard to SEQUENCE UP/DOWN pushbutton. update that register in the LTC2937 RAM. 6) Observe the modified sequence-up order as the sup- Continue with the other channels: plies come up.
  • Page 14 Each supply can occupy any one of the 1023 available Re-Try Count sequence positions. Multiple supplies can occupy the same In the DC2313 demo board the LTC2937 is configured sequence position – for example, they could all occupy to re-try an unlimited number of times when it detects sequence position 3.
  • Page 15 Execute a RESTORE command to view the MONITOR_BACKUP register contents. The LTC2937 does not attempt to recover from the fault. Instead, it turns-off all of the supplies and retains all of its status register contents. This enables a thorough post- fault examination of status registers in the state they were when the fault occurred.
  • Page 16 Sequence-down before issuing a ClEAR command. If the LTC2937 is waiting, not re-trying, after a fault, turn it off (press the “SEQUENCE UP/DOWN” button to turn- off the PB_EN and GLOBAL_ON LEDs). The LTC2937 will retain state, but will be ready to sequence-up.
  • Page 17 EEPROM Fault Backup 4) Issue a RESTORE command (0x2D). This restores the clean MONITOR_BACKUP register contents from The LTC2937 stores information about the “first” fault that it EEPROM. It clears the STATUS_INFORMATION[12] detects into the EEPROM MONITOR_BACKUP register. The indicator bit. It also restores all configuration registers information is a copy of the MONITOR_STATUS_HISTORY from EEPROM.
  • Page 18 DEMO MANUAL DC2313A Dc2313a BoarD Description Figure 6. DC2313A Demo Board layout dc2313af...

  • Page 19: Parts List

    DEMO MANUAL DC2313A parts List ITEM REFERENCE PART DESCRIPTION MANUFACTURER/PART NUMBER Required Circuit Components C1, C7, C10, C17 CAP., 0.1µF, X5R, 16V, 10%, 0603 MURATA, GRM188R61C104KA01D C2, C11-C16 CAP., 2.2µF, X5R, 10V, 10%, 0603 MURATA, GRM188R61A225KE34D C3, C4 CAP., 0.01µF, X7R, 10V, 10%, 0603 AVX, 0603ZC103KAT2A C5, C9 CAP., 10µF, X5R, 16V, 10%, 0805...
  • Page 20 I.C, LTC2937IUHE, QFN28UHE-5×6 U2, U3 I.C., DUAL BUFFERS, TSOP-6 NXP, 74LVC2G07GV,125 LINEAR TECH., LTC2954IDDB-2 I.C., PUSH BUTTON, DFN8DDB-3×2 I.C., LINEAR REG - 5V, TSOT23-5 LINEAR TECH., LT1761ES5-5 I.C., DIODE OR, MSE16 LINEAR TECH., LTC4415IMSE U7, U8, U9 I.C ANALOG SWITCH, SO16 LINEAR TECH, LTC222CS I.C SERIAL EEPROM, TSSOP8...

  • Page 21: Schematic Diagram

    DEMO MANUAL DC2313A schematic Diagram dc2313af...
  • Page 22 DEMO MANUAL DC2313A schematic Diagram dc2313af...
  • Page 23 Information furnished by Linear Technology Corporation is believed to be accurate and reliable. However, no responsibility is assumed for its use. Linear Technology Corporation makes no representa- tion that the interconnection of its circuits as described herein will not infringe on existing patent rights.
  • Page 24 Linear Technology Corporation (LTC) provides the enclosed product(s) under the following AS IS conditions: This demonstration board (DEMO BOARD) kit being sold or provided by Linear Technology is intended for use for ENgINEERINg DEVElOPMENT OR EVAlUATION PURPOSES ONlY and is not provided by LTC for commercial use. As such, the DEMO BOARD herein may not be complete in terms of required design-, marketing-, and/or manufacturing-related protective considerations, including but not limited to product safety measures typically found in finished commercial goods.