DC1592A - Demo Manual

Demo Circuit 1592A-A/-B
QUICK START GUIDE
LTC3577-3
and LTC3577-4
LTC3577-3 AND
LTC3577-4
Highly Integrated Portable
Product PMIC
DESCRIPTION
WARNING!
Do not look directly at operating LED.
This circuit produces light that can damage eyes.
Demo Circuit 1592A is a Highly Integrated Portable
Product PMIC with a pushbutton controller, two LDOs,
three buck converters, a Li-Ion battery charger, and a
power path controller featuring the LTC3577-3 and
LTC3577-4. This board utilizes a DC590B, USB to I2C
interface board, to control the LTC3577-3/LTC377-4
software control window.
The LTC3577-3 and LTC3577-4 are PowerPath™ manager with automatic load prioritization, battery charger,
Bat-Track™ controller, push button controlled power up
sequence and reset, and a 10 LED string controller with
gradation and PWM control. The three buck regulators
and the LED Boost controller have adjustable slew rates
for EMI reduction.
The LTC3577-3 and LTC3577-4 has a high temperature
battery voltage reduction feature that reduces the battery
voltage under high temperature conditions to improve
safety and reliability.
Refer to the LTC3577-3 and LTC3577-4 datasheet for
more details on the electrical and timing specifications.
Design files for this circuit board are available. Call
the LTC factory.
L, LTC, LTM, LT are registered trademarks of Linear Technology Corporation. PowerPath
and Bat-Track are trademarks of Linear Technology Corporation. All other trademarks are the
property of their respective owners.
PERFORMANCE SUMMARY Specifications are at TA = 25°C
PARAMETER
Input Supply Range (VBUS)
Absolute Wall Input Threshold (VW)
DVCC Operating Voltage
DVCC UVLO (VDVCC,UVLO)
VBAT Regulated Output Voltage (VFLOAT)
Constant Current Mode Charge Current (ICHRG)
VOUT UVLO
VOUT1
VOUT2
VOUT3
LDO1
LDO2
Full-Scale LED Current
CONDITIONS
VWALL Rising
VWALL Falling
DC1592A-A (LTC3577-3)
DC1592A-B (LTC3577-4)
RPROG = 2KΩ, Input current limit = 1A
VOUT Falling
VOUT Rising
0 to 500mA
0 to 500mA
0 to 800mA
0 to 150mA
0 to 150mA
MIN
4.35
3.1
1.6
4.179
4.079
465
2.5
TYP
4.3
3.2
MAX
5.5
4.45
5.5
1
4.200
4.100
500
2.7
2.8
1.8
3.3
1.2
3.3
1.2
20
4.221
4.121
535
2.9
UNITS
V
V
V
V
V
V
V
mA
V
V
V
V
V
V
V
mA
1
LTC3577-3 AND LTC3577-4
QUICK START PROCEDURE
Demo Circuit 1592 is designed to be used with a USB
input and/or a 5V adaptor input. Demo Circuit 1592 utilizes the DC590B, USB to I2C interface board, to control
the LED boost driver, LDO enables, and buck modes. It is
also used to monitor the buck and LDO outputs, plus
battery charger status. This circuit may be evaluated using a lithium ion battery or a battery simulator consisting of a 0V-5V, 3A power supply and a 3.6Ω power
resistor.
6. With power off, connect a 5V, 1A power supply to
VUSB and GND with a series ammeter and a voltmeter
as shown in Figure 1.
The DC1592 is easy to set up to evaluate the performance of the LTC3577-3 and LTC3577-4. Refer to Figure 1
and Figure 2 for proper measurement equipment setup
and follow the procedure below to evaluate using the
DC590B board:
9. Run the QuikEval.exe program. The LTC35773/LTC3577-4 control window (shown in Figure 3)
pops up.
X
X
NOTE. When measuring the input or output voltage ripple, care must be
taken to avoid a long ground lead on the oscilloscope probe. Measure the
input or output voltage ripple by touching the probe tip directly across
the VUSB, WALL, or VOUT and GND terminals. See Figure 2 for proper
scope probe technique.
X
X
1. Refer to the DC590B Quick Start Guide for QuikEvalTM
setup and software installation details.
2. Set the VCCIO jumper, JP6, on the DC590B board to
the 3.3V position.
NOTE. The DVCC voltage level may be selected on the DC590B. This is
done by setting the VCCIO jumper, JP6, on the DC590B board to one of
the following settings: 3.3V, 5V, removed for 2.7V or set to external if an
external supply is desired to be used.
3. Make sure the USB cable is connected between the
computer and the DC590B controller board.
4. Set the jumpers on the DC1592 board to the following
settings:
JP1. ILIM0 to “0” position.
JP2. ILIM1 to “0” position.
JP3. NTC to “INT” position.
JP4. PWR_ON CNTL to “SW” position.
JP5. VINLDO2 to “VOUT” position.
5. Connect DC1592 to the DC590B USB Serial Controller
using the supplied 14-conductor ribbon cable as
shown in Figure 1.
X
2
X
X
X
7. Connect a battery or a battery simulator set to 3.6V
between BAT and GND with a series ammeter and a
voltmeter as shown in Figure 1.
X
X
8. Turn on and set the VUSB input power supply to 5V.
The DC590B board gets its power from the USB cable.
X
X
NOTE. The Status indicators on the software control window may display
“N/A” when an I2C ACK was not received. This occurs when the part is in
the power down (PDN) state or when DVCC is missing. Please refer to
the LTC3577 datasheet for more information on the PDN state.
10. On the LTC3577-3/LTC3577-4 control window, select the PWR_ON HI/LOW button. When “HI” is indicated on the button, the PWR_ON pin goes high and
the LDO2, VOUT1, and VOUT2 outputs sequence up.
VOUT POWER GOOD for each output is indicated on
the STATUS section on the control window.
11. On the LTC3577-3/LTC3577-4 control window, select the EN3 HI/LOW button. When “HI” is indicated
on the button, the EN3 pin goes high and the VOUT3
powers up. VOUT POWER GOOD for VOUT3 is indicated on the STATUS section on the control window.
12. On the LTC3577-3/LTC3577-4 control window, select the BUCK1 through BUCK3 MODE buttons to
switch the bucks into Burst mode. Observe the output
ripple and the quiescent current before and after
switching modes.
13. Select the desired BUCK SW SLEW RATE option button to switch between a fast rise-time for best efficiency to a slower rise time with better EMI performance.
14. Set the LED DAC REG vertical slider to a desired current level. The LED current and the LED DAC register
setting are displayed in the test boxes below the vertical slider. The LED full scale current (ILED(FS)) for this
circuit is 20mA.
LTC3577-3 AND LTC3577-4
I LED
=
DAC − 63 ⎞
⎛
I LED ( FS ) • 10 ^ ⎜⎝ 3 • 63 ⎟⎠
0.8V
I LED ( FS ) = R18 • 500
15. Select the LED EN/DIS button to turn on the LEDs.
Select the button again to turn off the LEDs.
16. Select the “460ms” GRADATION TIME option button
then select the LED EN/DIS button. Observe how the
LEDs turn on and off smoothly when the LED boost
circuit is enabled and disabled.
17. Select the “PWM” LED MODE option button. This
allows the LED intensity to be adjusted with the PWM
controls as well as the DAC register.
18. Set the “PWM Numerator” and the “PWM Denominator” vertical sliders to their maximum position. The
hexadecimal value of “F” is displayed in the setting
text boxes below the sliders. The PWM duty cycle and
frequency are also displayed below the setting text
boxes.
PWMNUM
Duty Cycle =
PWMDEN
Frequency =
PWMCLK
PWMDEN
19. With the LED boost enabled, reduce the “PWM Numerator” vertical slider while observing the LED intensity. Notice that the LEDs dim as the numerator is decreased.
20. Select a different “PWM Clock Speed” option button
and observe the PWM frequency changes accordingly.
21. Set the WALL input, PS1, to 5V. Observe that the
input current is now coming from the WALL input instead of the VUSB input and VOUT.
22. Refer to the “USING THE LTC3577-3/LTC3577-4
SOFTWARE” section for more information on how to
control the device using the LTC3577-3/LTC3577-4
control window.
23. Set the “PWR_ON CNTL” jumper, JP4, to the “PB”
position to power up/down the device with the “ON”
pushbutton, PB1.
24. Depress the “ON” pushbutton, PB1 (minimum of
400ms). LDO2, VOUT1, and VOUT2 outputs sequence
up. If EN3 HI/LOW button is in the “HI” position,
VOUT3 will also power up. VOUT POWER GOOD for
each output is indicated on the STATUS section on the
control window.
25. Wait at least five seconds from depressing PB1, then
depress the “PWR_ON” pushbutton, PB2. LDO2,
VOUT1, and VOUT2 (VOUT3 if powered up) outputs
shutdown.
26. Again depress PB1, the “ON” pushbutton. LOD2,
VOUT1, and VOUT2 outputs sequence up.
27. Wait at least five seconds from depressing PB1, and
then depress and hold PB1 for at least 14 seconds.
PGOOD will transition low for 1.8ms to allow the microprocessor to reset.
28. The input current limit may be adjusted by changing
the “ILIM0” and “ILIM1” jumpers, JP1 and JP2 respectively. See Table 1 for details.
Table 1. Input Current Limit Settings
ILIM1
ILIM0
CURRENT LIMIT
0
0
100mA (1X)
0
1
1A (10X)
1
0
0.5mA (SUSP)
1
1
500mA (5X)
29. Refer to the LTC3577-3 and LTC3577-4 datasheet
for more details on how the LTC3577 operates.
30. When done, turn off all loads and power supplies
and then close the LTC3577-3/LTC3577-4 control window.
3
LTC3577-3 AND LTC3577-4
Proper Measurement Equipment Setup
GND
VIN
Figure 1. Measuring Input or Output Ripple
USING THE LTC3577-3/LTC3577-4 SOFTWARE
The LTC3577-3/LTC3577-4 program provides control of
the mode and slew rate of the buck regulators. It also
controls the intensity and slew rate of the LED boost controller and allows the user to view the contents of the
status register.
4
VIEW LTC3577 PRODUCT PAGE button opens an internet browser and searches the Linear Technology Corporation web site for information on the LTC3577 when an
internet connection is available.
LTC3577-3 AND LTC3577-4
REG0 through REG3 text box windows display the hexadecimal value that has been written to the corresponding
registers of the LTC3577-3/LTC3577-4.
STATUS REG text box window displays the hexadecimal
value that has been last read from the LTC35773/LTC3577-4 status register.
BUCK1 through BUCK3 MODE select buttons are used to
individually set each buck regulator into Pulse Skip Mode
or Burst Mode for light loads.
BUCK SW SLEW RATE option buttons are used to
choose one of four slew rates for optimal EMI reduction
or efficiency.
LED MODE option buttons are used to choose one of
three Boost controller modes. CC Boost mode is a constant current mode that allows the LED current to be
controlled by the LED DAC REG vertical slider. HV Boost
mode regulates the ILED pin to 0.8V to operate the Boost
at a fixed voltage. HV Boost mode should not be enabled
unless the demo circuit has been modified to support
this mode of operation. PWM mode allows the LED intensity to be controlled by pulse width modulating the
LEDs based on the LED DAC REG, PWM Numerator,
PWM Denominator, and PWM Clock Speed settings.
NOTE: When in CC Boost or HV Boost LED modes, the PWM controls
are disabled.
PWR_ON HI/LOW select button is used to set the
PWR_ON pin high or low to turn on or off LDO2, VOUT1,
and VOUT2.
GRADATION TIME option buttons set the desired time to
gradate up to or down from the selected LED intensity
whenever the LED controller is enabled or disabled.
EN3 HI/LOW select button is used to set the EN3 pin high
or low to turn on or off VOUT3.
LED DAC REG vertical slider controls the LED current
from 20uA to 20mA in 64 logarithmic steps. The LED
intensity slider may be adjusted by clicking on the up or
down arrows to increment or decrement by one LSB or
by clicking and dragging the slide pointer. The hex code
and LED current is displayed in the two text boxes below
the slider.
AUTO READ BACK ENABLED/DISABLED select button is
used to automatically update the status register every
250ms when enabled. When disabled the read register
may be updated by selecting the “Read Back Status” button.
Read Back Status button is used to update the status
register when selected.
AUTO UPDATE ENABLED/DISABLED select button is
used to automatically update the LTC3577-3/LTC3577-4
I2C registers when any of the Buck or LED buttons or
sliders have been changed. When disabled the LTC35773/LTC3577-4 I2C registers may be updated by selecting
the “Update All Registers” button.
Update All Registers button is used to update all of the
LTC3577-3/LTC3577-4 I2C write registers when selected.
LED EN/DIS select button is used to enable or disable the
LED boost controller.
BOOST SW SLEW RATE FAST/SLOW button is used to
turn on and off the LED switch faster or slower for optimal efficiency or EMI reduction.
PWM Clock Speed option buttons are used to select the
PWM clock speed. The PWM clock speed is divided by
the PWM denominator to determine the PWM frequency.
PWM Numerator vertical slider is used to select a PWM
numerator value. The PWM numerator is divided by the
PWM denominator to determine the PWM duty cycle.
PWM Denominator vertical slider is used select a PWM
denominator value. The PWM denominator is used in
conjunction with the PWM numerator to determine the
PWM duty cycle and with the PWM clock speed to determine the PWM frequency.
STATUS indicators display the charge, NTC, and power
status determined by the LTC3577-3/LTC3577-4 status
register.
5
LTC3577-3 AND LTC3577-4
Figure 2. LTC3577-3/LTC3577-4 Software Control Window
6
LTC3577-3 AND LTC3577-4
7
LTC3577-3 AND LTC3577-4
8
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