DEMO MANUAL DC1830B-A/DC1830B-B LTC4000 Battery Charger Controller and PowerPath Manager DESCRIPTION Demonstration circuit 1830B is a battery charger control- this part to control a switch mode power converter to form ler and PowerPath manager featuring the LTC 4000. a battery charger, intelligent PowerPath manager, and This board should be connected to a front end DC/DC power supply system. It produces a regulated 5A/14.6V power supply for a complete charger solution. battery charger output as well as a system output of up to 5.5A: suitable for a wide variety of portable applications The DC1830B is customizable to handle a wide variety of including instruments, industrial equipment, power tools, applications with output voltages from 3V to 30V and out- and computers. put currents up to 6.5A with the PFETs supplied, and up to 60V and/or 13A with higher voltage rating and/or added The DC1830B-A provides a solution complete with both PFETs. The reference design provided with DC1830A is battery charger control and PowerPath management. It targeted at 4-cell LiFePO (14.6V/5A) applications. includes a second PFET (Q2) between V and BAT 4 OUT-SYS to provide instant-on functionality which keeps V OUT-SYS The DC1830B loop compensation values were proven within a narrow range regardless of battery voltage, and with the LTC3845A buck-boost power converter shown disconnects the battery when it is fully charged and and are typical for other applications. The output of power is available from the front end DC/DC converter. this demo board was specifically tailored for a Tenergy Thermal regulation circuitry is also provided to limit the 10A-hour battery, P/N 30207. Other voltages can be set temperature of both PFETs. The DC1830B-B provides a by changing R and R . The desired nominal volt- OFB2 BFB2 simple battery-charger-controller only solution without age can be accurately trimmed by using trim resistors the PowerPath manager. It deletes the second PFET and R and R . For example, for 14.4V battery float OFBX BFBX thermal regulation circuitry. In this case, the battery is voltage, change R and R to 86.6k, and add 7.5M OFB2 BFB2 always online and V tracks BAT voltage. OUT-SYS at R and R for greater set point accuracy. Other OFBX BFBX parameters can be adjusted to suit specific applications Design files for this circuit board are available at with guidance provided in the LTC4000 data sheet. Table 2 DEMO MANUAL DC1830B-A/DC1830B-B QUICK START PROCEDURE Demonstration circuit 1830 is offered for use in combina- 3. Set CHARGE jumper to ENABLE. tion with a front end DC/DC converter, and will need to be 4. Turn on the power at the input. customized to suit the intended application. It has been NOTE: Make sure that the input voltage never supplied with components for a design as outlined in the exceeds 60V. performance summary, and tested in conjunction with the LTC3845A buck converter that it was tailored to. A sepa- 5. Check for the proper BAT output voltage of 14.6V. rate demonstration board is available for the LTC4000/ Turn off the power at the input. LTC3789 buck-boost combination, the DC1721A. The 6. Now that the proper output voltage is established, LTC4000 data sheet should be used for guidance in deter- connect a variable load capable of sinking 6A at 16V mining circuit values for the application at hand. You may to the output terminals BAT and GND. Set the current follow the design example on page 26 of the data sheet. for 0A. Table 1 provides a summary of parameter adjustments. 7. Turn on the power at the input. NOTE: The PFETs supplied on this board are rated at 30V. NOTE: If there is no output, temporarily disconnect Once the circuit has been customized to suit the appli- the load to make sure that the load is not set too high. cation at hand, it is easy to set up to evaluate the per- formance of the LTC4000 when combined with a suit- 8. Once the proper BAT output voltage is again estab- able switching power converter, such as the LTC3845A. lished, adjust the load and/or source within the oper- voltages and currents cited in this procedure are for the ating range and observe the battery float voltage regu- design as delivered if the design has been customized, lation, charge current, and other desired parameters. substitute the appropriate values. Refer to Figure 1 for 9. Set the load to constant voltage mode to more easily proper measurement equipment setup and follow the observe charge current and trickle charge current. procedure below: NOTE: The following applies to the DC1830B-A. WARNING: BATTERIES ARE POTENTIALLY DANGEROUS NOTE: Operation in the instant-on region (V < HIGH ENERGY SOURCES. IMPROPER CONNECTION, OUT 12.5V) may engage thermal limit circuit to protect OVERCHARGE, OR RAPID DISCHARGE COULD RESULT Q2 in the linear region. IN EXPLOSION AND/OR FIRE. NOTE: The optional thermal limit circuit for Q1 (Q5, 1. Set an input power supply that is capable of 60V and RNTC3, R8 to 12, and U2) is included to protect Q1 in 3A, to 24V. Then turn off the supply. case of an extended short-circuit on VOUT-SYS under 2. With power off, connect the supply to the input ter- adverse thermal conditions (T > 40C). It may not be A minals VIN and GND. needed in applications with less severe thermal condi- NOTE: tions, lower current available to VOUT-SYS, or where continuous short-circuit protection on VOUT-SYS is a. Input voltages lower than 20V can keep the con- not required. verter from turning on due to the undervoltage lockout feature of the LTC4000. b. If efficiency measurements are desired, refer to Figure 1 for the test setup. Rev. A 2