LTC3586EUFE DEMO CIRCUIT 1306 QUICK START GUIDE LTC3586EUFE High Efficiency USB Power Manager + Dual Buck + Boost + Buck-Boost DC/DC DESCRIPTION Demonstration Circuit 1306 is a High Efficiency USB Unlike linear PowerPath controllers, the LTC3586s Power Manager plus Dual Buck plus Multi-Output switching input stage can use nearly all of the 0.5W Power Supply featuring the LTC 3586. The LTC3586 or 2.5W available from the USB port with minimal integrates a high efficiency USB Li-Ion battery power dissipation. This feature allows the LTC3586 charger with PowerPath control and four general to provide more power to the application and eases purpose switching regulators, all in one chip. The thermal issues in constrained applications. An ideal PowerPath manager includes a synchronous diode ensures that system power is available from switching low voltage input regulator, a full-featured the battery when the input current limit is reached or if the USB or wall supply is removed. The LTC3586 battery charger and an ideal diode. Designed specifically for USB applications, the LTC3586s low includes two 400mA buck regulators, one 1A buck- voltage switching regulator automatically limits its boost regulator and one 800mA boost regulator for a input current to a maximum of either 1x (for USB variety of handheld applications. 100mA), 5x (for USB 500mA) or 10x for wall- Design files for this circuit board are available. Call powered applications (1A). The switching input stage the LTC factory. provides power to VOUT where power sharing between the application circuit and the battery L, LTC, LTM, LT, Burst Mode, are registered trademarks of Linear Technology Corporation. charger is managed. All other trademarks are the property of their respective owners. TABLE 1. Typical Specifications (25C) 4.35V to 5.5V Input Voltage Range: V CC VOUT 3.4V to 4.7V, 1.5A (Max) LDO3V3 3.1V to 3.5V, 25mA (Max) Buck VOUT1 1.16V to 1.26V, 400mA (Max) Buck VOUT2 1.69V to 1.90V, 400mA (Max) Buck VOUT3 3.13V to 3.51, 1.0A (Max) Buck-Boost VOUT4 4.74V to 5.26V 800mA (Max) Boost 1 LTC3586EUFE OPERATING PRINCIPLES The LTC3586 is a highly integrated power manage- The PowerPath switching regulator and battery ment IC which includes a high efficiency switch charger communicate to ensure that the input cur- mode PowerPath controller, a battery charger, an rent never violates the USB specifications. ideal diode, an always-on LDO, two 400mA buck The ideal diode from BAT to VOUT guarantees that switching regulators, a 1A buck-boost switching ample power is always available to VOUT even if there regulator, and an 800mA boost switching regulator. is insufficient or absent power at VBUS. All of the regulators can be independently controlled An always on LDO provides a regulated 3.3V from available power at VOUT. Drawing very little quiescent via ENABLE pins. Designed specifically for USB applications, the Po- current, this LDO will be on at all times and can be werPath controller incorporates a precision average used to supply up to 20mA. input current buck switching regulator to make max- Along with constant frequency PWM mode, the buck imum use of the allowable USB power. Because and the buck-boost switching regulators have a low power is conserved, the LTC3586 allows the load power burst mode setting for significantly reduced current on VOUT to exceed the current drawn by the quiescent current under light load conditions. USB port without exceeding the USB load specifica- tions. QUICK START PROCEDURE Using short twisted pair leads for any power connec- 1. Jumper, PS and LOAD Settings to start: tions and with all loads and power supplies off, refer JP1 (NTC) = INT PS1 = OFF to Figure 1 for the proper measurement and equip- JP2 (ILIM0) = 0 PS2 = NC ment setup. The Battery should not be connected to JP3 (ILIM1) = 0 LOAD1 = OFF the circuit until told to do so in the procedure below. JP4 (MODE) = 0 LOAD2 = OFF JP5 (EN1) = OFF LOAD3 = OFF When measuring the input or output voltage ripple, care JP6 (EN2) = OFF LOAD4 = OFF must be taken to avoid a long ground lead on the oscillo- JP7 (EN3) = OFF LOAD5 = OFF scope probe. Measure the input or output voltage ripple JP8 (EN4) = OFF LOAD6 = OFF by touching the probe tip directly across the VCC or NC: Not Connected VOUT and GND terminals. See Figure 2 for proper scope 2. Turn on PS1 and slowly increase voltage until probe technique. the voltage at VBUS is 4.35V while monitoring input current. If input current exceeds 200mA turn off PS1 and look for shorts. 3. Turn on LOAD1 and LOAD2. Set LOAD1 on LDO3V3 to 5mA and LOAD2 on VOUT to 50mA in constant current mode. 2