DC1033B - Demo Manual

DEMO MANUAL DC1033B
LTC2952
Pushbutton On/Off
Power Path Controller
DESCRIPTION
Demonstration circuit 1033B features the LTC©2952, a micropower, multipurpose, pushbutton On/Off PowerPath™
controller that provides voltage monitoring and supervisory
features, as well as ideal diode power paths. Selectable
PowerPath management modes allow a variety of power
on and off configurations, including pushbutton on/off
control and voltage detection on/off control.
The LTC2952’s pushbutton input has independently programmable ON and OFF de-bounce times. A simple microprocessor interface allows for proper system housekeeping
prior to power down. The status of digital pins G1STAT,
PFO, RST and INT are displayed with LEDs. Under system
fault conditions, the part’s internal KILL timer ensures that
the system can be shut down. High reliability systems may
PERFORMANCE SUMMARY
utilize the LTC2952’s power fail, voltage monitoring, diode
status, watchdog and μP reset features to monitor power
status and ensure system integrity.
The DC1033B operates over the full LTC2952 range of 2.7V
to 28V to accommodate a wide variety of input power supplies. Low forward drop ideal diodes and very low standby
current (25μA typ) make the LTC2952 ideally suited for
battery powered or power conscious applications.
Design files for this circuit board are available at
http://www.linear.com/demo/DC1033B
L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks and
PowerPath is a trademark of Linear Technology Corporation. All other trademarks are the
property of their respective owners.
Specifications are at TA = 25°C
PARAMETER
CONDITIONS
VALUE
Input Voltage Range
V1 and/or V2
2.7V to 28V
Output Voltage VS
Configuration A
V1 or V2*
Configuration B
V1 or V2*
Configuration C, Pushbutton Enable On
V1 or V2*
Configuration D, Pushbutton Enable On, V2 > V2 Threshold
V1 or V2*
DC/DC Out 2P6V
Configuration A-D, Pushbutton Enable On
2.6V
V2 Trip Threshold
Default Resistors (R9 and R10), JP2 Set to Monitor V2
4.725V
Power Fail Input Voltage PFI
Default Resistors (R3 and R4) Monitor VS
3.055V
Resistor Options (R17 and R4) Set to Monitor V2
3.055V
Voltage Monitor VM
Pushbutton On Time ONT
Pushbutton Off Time OFFT
Default Resistors (R1 and R2) Monitor 2P6V
2.325V
Resistor Options (R16 and R2) Set to Monitor VS
3.055V
JP3 Set to OPEN, LTC2952 Default ONT
26ms
JP3 Set to CAP to Connect 22nF to ONT Pin
26ms + 205ms
JP4 Set to OPEN, LTC2952 Default OFFT
26ms
JP4 Set to CAP to Connect 68nF to OFFT Pin
26ms + 632ms
* VS will be the ideal diode OR of V1 and V2. There is only a slight voltage drop across the ideal diode.
dc1033bf
1
DEMO MANUAL DC1033B
QUICK START PROCEDURE
(Configuration A)
2. Connect a voltmeter across VS and GND.
Demonstration circuit 1033B is easy to set up to evaluate the
performance of the LTC2952. Refer to Figure 1 for proper
measurement equipment setup and follow the procedure
below. This Quick Start Procedure sets up the DC1033B
for Configuration A. See Operating Principles for further
description of the different configurations
3. Apply a voltage of 2.7V to 28V across V2 (WALL).
1. Place jumpers in the following positions:
JP1:
LO
JP2:
LO
JP3:
CAP
JP4:
CAP
JP5:
UNTIE
V2
WALL
2.7V-28V
4. Apply a voltage of 2.7V to 28V across V1 (BAT).
5. Measure VS, which will be the ideal diode OR of the
higher supply V2 or V1.
6. Push down once and hold on Pushbutton SW1 for a
Turn On. Observe both SUP_EN and RST LEDs turn
on. After a short period, RST turns off.
7. Push down again and hold on Pushbutton SW1 for a
Turn Off. Observe while SUP_EN LED is on, INT LED
turns on momentarily. After a short period, both SUP_EN
and INT LEDs turn off.
Note: LED sequence in steps 6 and 7 are the same for
configurations A through D.
+
–
V1
BATTERY
2.7V-28V
PUSHBUTTON
dc1033b F01
Figure 1. Basic Equipment Setup
2
dc1033bf
DEMO MANUAL DC1033B
OPERATING PRINCIPLES
The DC1033B operates from 2.7V to 28V applied to either
V1 or V2. Configuration of M1 and M2 of the LTC2952
determines the power path to the output voltage and the
example DC/DC converter (U4). P-Channel MOSFETs U2
and U3 are driven by the LTC2952 for the ideal diode
feature providing a low forward voltage drop. J1 and J2
provide a bypass option if one or both of the PFETs in U3
are not needed. A pushbutton turns on and off the Enable
that drives the DC/DC converter and in some configuration
also turns on and off the ideal diode power paths. The
pushbutton on and off times are set by jumper selectable
external capacitors. The status of G1STAT indicates the
status of G1. PFO gives an output signal (shown with an
LED) if voltage at the PFI input is below the threshold.
RST and INT provide maintenance to a microprocessor
on a power up or power down. Immediate shutdown can
be done by pulling low on KILL.
CONFIGURATION A
(M1 low, M2 low): Pushbutton Controller with Automatic
Load Switching Between WALL and Battery
Set both JP1 (M1CONFG) and JP2 (M2CONFG) to LO to
enable both ideal diodes always. VS will be the ideal diode
OR of V1 and V2 where VS equals the higher of the two
supplies minus the slight ideal diode drop. G1STAT LED
turns on when V2 > V1. The pushbutton turns on and off the
EN pin which drives the shutdown of the DC/DC converter.
CONFIGURATION B
(M1 low, M2 monitor): Pushbutton Controller with Preferential WALL Operation and Automatic Load Switching
to Battery
Set JP1 (M1CONFG) to LO and JP2 (M2CONFG) to V2MON
to configure M2 as a monitor on the Wall Adapter voltage
V2. When V2 is above the trip threshold, the ideal diode
for V2 is turned on always, while the ideal diode for V1
is shutdown, even if V1 is greater than V2. VS will then
equal V2 minus the ideal diode voltage drop.
When V2 falls below the trip threshold, both ideal diodes
are enabled. VS will be the ideal diode OR of V1 and V2
where VS equals the higher of the two supplies minus the
slight ideal diode drop. The pushbutton turns on and off the
EN pin which drives the shutdown of the DC/DC converter.
CONFIGURATION C
(M1 high, M2 high): Pushbutton Control of Ideal Diodes
Drivers
Set JP1 (M1CONFG) to HI and JP2 (M2CONFG) to TIEM1.
M1 has an internal pull-up current and pulls up M2 as
well when tied together. This sets up the pushbutton to
have full control on both ideal diodes and the EN pin. On
a pushbutton turn on, both ideal diode drivers are turned
on as well as the DC/DC converter. VS will be the ideal
diode OR of V1 and V2 where VS equals the higher of the
two supplies minus the ideal diode drop. On a pushbutton turn off, both ideal diode drivers are shutdown and
VS is turned off.
CONFIGURATION D
(M1 high, M2 monitor): Battery Backup with Pushbutton
Power Path Controller
Set JP1 (M1CONFG) to HI and JP2 (M2CONFG) to V2MON.
M1 is set high due to its internal pull-up current. M2 monitors V2. When V2 is below the trip threshold, both ideal
diodes are shutdown always and the input to the PB pin is
ignored. When V2 is above the trip threshold, the pushbutton has full control of the EN pin and ideal diode drivers.
Also while M1 is high, a transition on M2 will force a
pushbutton turn on or turn off. To test this, move the V2
input to be above and below the trip threshold.
dc1033bf
3
DEMO MANUAL DC1033B
OPERATING PRINCIPLES
ONT/OFFT PROGRAMMING
VOLTAGE MONITORS PFI AND VM
Additional pushbutton turn on and off de-bounce time
can be set by attaching a capacitor from the ONT and
OFFT pins to GND and can be done through JP3 and
JP4, respectively, on the DC1033B. Select OPEN for the
Internal Default Time of the LTC2952 only or choose CAP
for additional timing. See figures 2, 3, 4 and 5 for timing
differences. The additional timing can be calculated using
the following equations:
Voltage monitoring is also provided by the Power Fail
Input (PFI) and Voltage Monitor (VM) pins. If the voltage
at PFI falls below its threshold, a signal is given at PFO
and shown with an LED. If the voltage at VM falls below
its threshold, a signal is given at RST and also shown
with an LED. RST is typically connected to the Reset of a
microcontroller to reset the device and halt operation until
the supply voltage is above a specified voltage.
tONT = CONT [F] • 9.3 x 106 [Ω]
tOFFT = COFFT [F] • 9.3 x 106 [Ω]
INT/KILL
The INT pin can be tied to the KILL pin through JP5
to immediately shutdown when INT pulls low during a
turn off sequence. When the pins are untied, the INT pin
becomes open collector for the interrupt period before
power is turned off.
4
WATCHDOG AND EXTEND FUNCTION WITH WDE
During a shutdown process after the INT pin goes high
impedance, a rising or falling edge on the WDE pin within
a 500ms period extends the waiting period before the EN
line is set low. See figure 6 and 7 for timing comparison.
The WDE pin can also be used with the VM pin to provide
a watchdog timer.
Figure 2. Pushbutton Turn ON with No Additional Timing
dc1033bf
DEMO MANUAL DC1033B
OPERATING PRINCIPLES
Figure 3. Pushbutton Turn ON with 22nF at ONT
Figure 4. Pushbutton Turn OFF with No Additional Timing
Figure 5. Pushbutton Turn OFF with 68nF at OFFT
dc1033bf
5
DEMO MANUAL DC1033B
OPERATING PRINCIPLES
6
Figure 6. Pushbutton Turn OFF with No WDE Extension
Figure 7. Pushbutton Turn OFF with Transitions at WDE for Time Extension
dc1033bf
DEMO MANUAL DC1033B
PCB LAYOUT
Top Layer
Layer 2
dc1033bf
7
DEMO MANUAL DC1033B
PCB LAYOUT
Layer 3
Bottom Layer
8
dc1033bf
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 representation that the interconnection of its circuits as described herein will not infringe on existing patent rights.
A
B
C
D
GND
PB#
M1
M2
PFI
GND
V1(BAT)
2.7V - 28V
GND
E8
E9
LO
HI
E18
E17
E15
E21
E10
E20
5
JP1
R10
100k
1%
1%
LO
TIEM1
R12
1k
CV1
OPT
50V
PB#
M1
M2
PFI
V2
V1
G1
CAP
OPEN
JP3
ONT
PB#
SW1
4
19
18
2
13
15
16
PB#
M1
M2
PFI
V2
V1
G1
4
3
J2
0 (OPT)
NOTE 4
3
NOTE 2
J1
0 (OPT)
U1
LTC2952
5
8
PFO#
RST#
INT#
KILL#
WDE
6
5
10
20
3
JP4
OPEN
G1STAT
17
OFFT
EN
D4
GRN
SUP_EN
11
CAP
/SHDN
IN
R11
100
3
THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND
SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS.
CUSTOMER NOTICE
1
R18
100k
2
1
D3
ORN
PFO#
R6
100
2
R14
100k
1%
R13
105k
1%
2
SCALE = NONE
DILIAN R.
KIM T.
APPROVALS
D2
ORN
G1STAT
R7
100
LT3010EMS8E
U4
ADJ
OUT
LINEAR TECHNOLOGY HAS MADE A BEST EFFORT TO DESIGN A
CIRCUIT THAT MEETS CUSTOMER-SUPPLIED SPECIFICATIONS;
HOWEVER, IT REMAINS THE CUSTOMER'S RESPONSIBILITY TO PCB DES.
VERIFY PROPER AND RELIABLE OPERATION IN THE ACTUAL
APPLICATION. COMPONENT SUBSTITUTION AND PRINTED
APP ENG.
CIRCUIT BOARD LAYOUT MAY SIGNIFICANTLY AFFECT CIRCUIT
PERFORMANCE OR RELIABILITY. CONTACT LINEAR
TECHNOLOGY APPLICATIONS ENGINEERING FOR ASSISTANCE.
2
COFFT 1
0.068uF
2
WDE
KILL#
INT#
RST#
PFO#
G1STAT
EN
CVS
0.47uF
50V
VS
3
CONT
0.022uF
VM
3
1. ALL RESISTORS AND CAPACITORS ARE 0603.
2. BYPASS V1 SECOND FET OPTION WITH 0 OHM RESISTOR.
3. BYPASS V2 SECOND FET OPTION WITH 0 OHM RESISTOR.
4. REMOVE R3 AND INCLUDE R17 TO MONITOR V2 AT PFI.
5. REMOVE R1 AND INCLUDE R16 FOR VM TO MONITOR VS
INSTEAD OF DC/DC OUTPUT VOLTAGE.
6. CV1, CV2 SHOULD BE SMALL IF NEEDED.
JP2
1
3
V2MON
R3
511k
U3
Si7923DN
NOTE: UNLESS OTHERWISE SPECIFIED
2
1
C2
1nF
16V
VS
M2CONFG
6
5
R4
100k
1%
R17
511k
1%
OPT
4
R9
845k
1%
NOTE 3
2
M1CONFG
3
C1
0.1uF
50V
U2
Si7923DN
6
8
CV2
OPT
50V
3
D2
D1
5
D2
D1
7
G2
4
S2
S1
1
G1
2
V2(WALL)
2.7V - 28V E11
1
2
2
D1
4
G2
G1
1
D2
6
D2
D1
5
S2
GND
9
1
2
GND
4
GND
9
1
2
S1
21
1
2
7
7
1
2
8
G2
12
G2
ONT
8
GND
VS
14
VS
OFFT
1
VM
D5
RED
INT#
R8
100
1
R15
100k
1%
R2
100k
R1
365k
1%
E7
E6
E5
E4
E3
E2
E1
E14
E13
1
JP5
E19
DILIAN R.
APPROVED
GND
WDE
KILL#
INT#
RST#
PFO#
G1STAT
EN
2P6V
VM
GND
VS
1
DATE
08-31-15
DATE:
N/A
SIZE
1
LTC2952CUF
DEMO CIRCUIT 1033B
Monday, August 31, 2015
IC NO.
SHEET
1
OF
1
1
REV.
PUSHBUTTON ON/OFF POWERPATH CONTROLLER
1630 McCarthy Blvd.
Milpitas, CA 95035
Phone: (408)432-1900 www.linear.com
Fax: (408)434-0507
LTC Confidential-For Customer Use Only
TIE
INT# / KILL#
3
UNTIE
2
NOTE 5
R16
511k
1%
OPT
E22
E12
REBUILD WITH CHANGE
DESCRIPTION
REVISION HISTORY
TECHNOLOGY
REV
TITLE: SCHEMATIC
D1
ORN
RST#
R5
100
CO
0.47uF
2P6V
__
ECO
1
2
4
TO MICROPROCESSOR
5
A
B
C
D
DEMO MANUAL DC1033B
SCHEMATIC DIAGRAM
dc1033bf
9
DEMO MANUAL DC1033B
DEMONSTRATION BOARD IMPORTANT NOTICE
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. As a prototype, this product does not fall within the scope of the European Union
directive on electromagnetic compatibility and therefore may or may not meet the technical requirements of the directive, or other regulations.
If this evaluation kit does not meet the specifications recited in the DEMO BOARD manual the kit may be returned within 30 days from the date
of delivery for a full refund. THE FOREGOING WARRANTY IS THE EXCLUSIVE WARRANTY MADE BY THE SELLER TO BUYER AND IS IN LIEU
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engineer.
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1630 McCarthy Blvd.
Milpitas, CA 95035
Copyright © 2004, Linear Technology Corporation
10 Linear Technology Corporation
dc1033bf
LT 0116 • PRINTED IN USA
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