Demo Circuit 1402A QUICK START GUIDE LTC3577 and LTC3577-1 LTC3577 AND LTC3577-1 Highly Integrated 6-Channel Portable PMIC DESCRIPTION The LTC3577 has a high temperature battery voltage re- WARNING duction feature that reduces the battery voltage under high temperature conditions to improve safety and reli- Do not look directly at operating LED. ability. This circuit produces light that can damage eyes. The high voltage (HV) buck interface is designed to con- nect to and control an external HV buck regulator demo Demo Circuit 1402 is a Highly Integrated 6-Channel board via the Bat-Track control circuitry. Some of these Portable PMIC with a push button controller, two LDOs, demo boards are the DC1394A, DC1395A, and DC1325A, three buck converters, a Li-Ion battery charger, a Power- featuring the LT3480, LT3505, and the LT3563 HV bucks Path controller, and high voltage buck controller interface respectively. featuring the LTC3577 and LTC3577-1. Refer to the LTC3577 datasheet for more details on the The LTC3577 is a PowerPath manager with automatic electrical and timing specifications. load prioritization, battery charger, Bat-Track control- ler, push button controlled power up sequence and reset, Design files for this circuit board are available. Call and a 10 LED string controller with gradation and PWM the LTC factory. control. The three buck regulators and the LED Boost 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 controller have adjustable slew rates for EMI reduction. property of their respective owners. PERFORMANCE SUMMARY Specifications are at T = 25C A PARAMETER CONDITIONS MIN TYP MAX UNITS Input Supply Range (V ) NOTE: The input current limit is reduced when VBUS falls 4.35 5.5 V BUS below 4.45V (TYP). Absolute Wall Input Threshold (V) V Rising 4.3 4.45 V W WALL V Falling 3.1 3.2 V WALL DV Operating Voltage 1.6 5.5 V CC DV UVLO (V 1 V CC DVCC,UVLO) V Regulated Output Voltage (V ) LTC3577 4.179 4.200 4.221 V BAT FLOAT LTC3577-1 4.079 4.100 4.121 V Constant Current Mode Charge Current (I ) R = 2K, Input current limit = 1A 465 500 535 mA CHRG PROG V UVLO V Falling V 2.5 2.7 OUT OUT V Rising 2.8 2.9 V OUT V 0 to 500mA 3.3 V OUT1 V 0 to 500mA 1.8 V OUT2 V 0 to 800mA 1.2 V OUT3 LDO1 0 to 150mA 1.5 V LDO2 0 to 150mA 2.5 V Full-Scale LED Current 20 mA 1LTC3577 AND LTC3577-1 QUICK START PROCEDURE Demo Circuit 1402 is designed to be used with a USB 5. Connect DC1402 to the DC590B USB Serial Controller input and/or an external HV buck demo board, such as using the supplied 14-conductor ribbon cable as the DC1325A, DC1394A, or DC1395A featuring the shown in Figu re 1. LT3653, LT3480 and the LT3505 respectively. Demo Cir- 6. With power off, connect a 5V, 1A power supply to 2 cuit 1402 utilizes the DC590B, USB to I C interface VUSB and GND with a series ammeter and a voltmeter board, to control the LED boost driver, LDO enables, and as shown in Figure 1. buck modes. It is also used to monitor the buck and LDO 7. Connect a battery or a battery simulator set to 3.6V outputs, plus battery charger status. This circuit may be between BAT and GND with a series ammeter and a evaluated using a lithium ion battery or a battery simula- voltmeter as shown in Figure 1. tor consisting of a 0V-5V, 3A power supply and a 3.6 power resistor. Turn on and set the VUSB input power supply to 5V. 8. The DC590B board gets its power from the USB cable. The DC1402 is easy to set up to evaluate the perform- ance of the LTC3577 and LTC3577-1. Refer to Figure 1 NOTE. Make sure that the input voltage does not exceed 6V. and Figure 2 for proper measurement equipment setup Run the QuikEval.exe program. The LTC3577 control 9. and follow the procedure below to evaluate using the window (shown in Figure 3) pops up. DC590B board: NOTE. The Status indicators on the software control window may display NOTE. When measuring the input or output voltage ripple, care must be 2 N/A when an I C ACK was not received. This occurs when the part is in taken to avoid a long ground lead on the oscilloscope probe. Measure the the power down (PDN) state or when DVCC is missing. Please refer to input or output voltage ripple by touching the probe tip directly across the LTC3577 datasheet for more information on the PDN state. the Vin or Vout and GND terminals. See Figure 2 for proper scope probe technique. 10. On the LTC3577 control window, select the PWR ON TM HI/LOW button. When HI is indicated on the button, 1. Refer to the DC590B Quick Start Guide for QuikEval the PWR ON pin goes high and the VOUT1, VOUT2, setup and software installation details. and VOUT3 outputs sequence up. VOUT POWER 2. Set the VCCIO jumper, JP6, on the DC590B board to GOOD for each output is indicated on the STATUS the 3.3V position. section on the control window. NOTE. The DVCC voltage level may be selected on the DC590B. This is 11. Select the BUCK1 through BUCK3 MODE buttons to done by setting the VCCIO jumper, JP6, on the DC590B board to one of switch the bucks into Burst mode. Observe the output the following settings: 3.3V, 5V, removed for 2.7V or set to external if an external supply is desired to be used. ripple and the quiescent current before and after switching modes. 3. Make sure the USB cable is connected between the computer and the DC590B controller board. 12. Select the desired BUCK SW SLEW RATE option but- ton to switch between a fast rise-time for best effi- 4. Set the jumpers on the DC1402-2 board to the follow- ciency to a slower rise time with better EMI perform- ing settings: ance. JP1. PWR ON CNTL to SW position. 13. Select the LDO1 and LDO2 EN/DIS buttons to enable JP2. ILIM1 to 1 position. 2 LDO1 and LDO2 via the I C bus. JP3. ILIM0 to 1 position. 14. Set the LED DAC REG vertical slider to a desired cur- rent level. The LED current and the LED DAC register JP4. STATUS PIN PULL-UP to VOUT position. setting are displayed in the test boxes below the verti- JP5. NTC to INT position. cal slider. The LED full scale current (I ) for this LED(FS) JP6. VINLDO2 to VOUT position. circuit is 20mA. JP7. VINLDO1 to VOUT position. 2