Linear Technology Demo Circuit 1592A, Demo Circuit 1592A-A, Demo Circuit 1592A-B Quick Start Manual

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Demo Circuit 1592A-A/-B

QUICK START GUIDE

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

LTC3577-3 and LTC3577-4

LTC3577-3 AND LTC3577-4

Highly Integrated Portable

Product PMIC

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

PARAMETER CONDITIONS MIN TYP MAX UNITS

Input Supply Range (V Absolute Wall Input Threshold (VW) V

Operating Voltage 1.6 5.5

DVCC UVLO (V V

Regulated Output Voltage (V

BAT

Constant Current Mode Charge Current (I V

UVLO V

OUT

OUT1

OUT2

OUT3

LDO1 LDO2 Full-Scale LED Current 20 m

DVCC,UVLO)

BUS

)

) DC1592A-A (LTC3577-3)

FLOAT

CHRG

WALL

DC1592A-B (LTC3577-4)

) R

PROG

OUT

0 to 500mA 1.8 0 to 500mA 3.3 0 to 800mA 1.2 0 to 150mA 3.3 0 to 150mA 1.2

Specifications are at TA = 25°C

4.35 5.5 Rising Falling

= 2KΩ, Input current limit = 1A 465 500 535 m

Falling Rising

4.3

3.1

3.2

4.179

4.200

4.079

4.100

2.5 2.7

2.8 2.9

4.45

4.221

4.121

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 consist-

ing of a 0V-5V, 3A power supply and a 3.6Ω power resistor.

The DC1592 is easy to set up to evaluate the performance of the LTC3577-3 and LTC3577-4. Refer to

Figure 1X and Figure 2 for proper measurement equipment setup and follow the procedure below to evaluate using the DC590B board:

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 scope probe technique.

Figure 2X for proper

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.

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 1X.

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

Turn on and set the VUSB input power supply to 5V.

Figure 1X.

The DC590B board gets its power from the USB cable.

Run the QuikEval.exe program. The LTC3577-

3/LTC3577-4 control window (shown in pops up.

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.

Figure 3X)

10. On the LTC3577-3/LTC3577-4 control window, se-

lect 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, se-

lect 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, se-

lect 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 but-

ton to switch between a fast rise-time for best efficiency to a slower rise time with better EMI performance.

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 1X.

14. Set the LED DAC REG vertical slider to a desired cur-

rent 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 (I

LED(FS)

) for this

circuit is 20mA.

LTC3577-3 AND LTC3577-4

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 Denomi-

nator” 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.

19. With the LED boost enabled, reduce the “PWM Nu-

merator” 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

Frequency =

)(

FSLEDLED

)(

FSLED

CycleDuty =

⎛

••=

3^10

⎜ ⎝

8.0 500

•=

PWMNUM

PWMDE

PWMCLK

PWMDE

DAC

−

⎞ ⎟

⎠

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.

LTC3577-3 AND LTC3577-4

Proper Measurement Equipment Setup

VIN

GND

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.

VIEW LTC3577 PRODUCT PAGE

net browser and searches the Linear Technology Corporation web site for information on the LTC3577 when an internet connection is available.

button opens an inter-

REG0

through decimal value that has been written to the corresponding registers of the LTC3577-3/LTC3577-4.

STATUS REG

value that has been last read from the LTC35773/LTC3577-4 status register.

BUCK1

individually set each buck regulator into Pulse Skip Mode or Burst Mode for light loads.

BUCK SW SLEW RATE

choose one of four slew rates for optimal EMI reduction or efficiency.

PWR_ON HI/LOW

PWR_ON pin high or low to turn on or off LDO2, VOUT1, and VOUT2.

EN3 HI/LOW

or low to turn on or off VOUT3.

AUTO READ BACK ENABLED/DISABLED

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

AUTO UPDATE ENABLED/DISABLED

used to automatically update the LTC3577-3/LTC3577-4 I sliders have been changed. When disabled the LTC35773/LTC3577-4 I the “Update All Registers” button.

Update All Registers

LTC3577-3/LTC3577-4 I2C write registers when selected.

LED EN/DIS

LED boost controller.

BOOST SW SLEW RATE FAST/SLOW

turn on and off the LED switch faster or slower for optimal efficiency or EMI reduction.

through

C registers when any of the Buck or LED buttons or

REG3

text box windows display the hexa-

text box window displays the hexadecimal

BUCK3 MODE

select button is used to set the

select button is used to set the EN3 pin high

button is used to update the status

C registers may be updated by selecting

button is used to update all of the

select button is used to enable or disable the

select buttons are used to

option buttons are used to

select button is

button is used to

LTC3577-3 AND LTC3577-4

LED MODE

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 in-

tensity 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:

are disabled.

GRADATION TIME

gradate up to or down from the selected LED intensity whenever the LED controller is enabled or disabled.

LED DAC REG

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.

PWM Clock Speed

PWM clock speed. The PWM clock speed is divided by the PWM denominator to determine the PWM frequency.

PWM Numerator

numerator value. The PWM numerator is divided by the PWM denominator to determine the PWM duty cycle.

PWM Denominator

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

status determined by the LTC3577-3/LTC3577-4 status register.

option buttons are used to choose one of

When in CC Boost or HV Boost LED modes, the PWM controls

option buttons set the desired time to

vertical slider controls the LED current

option buttons are used to select the

vertical slider is used to select a PWM

vertical slider is used select a PWM

indicators display the charge, NTC, and power