|Title||BOARD EVAL FOR LTC4020EUHF|
|Company||Linear Technology Corporation|
|Datasheet||Download DC2044A datasheet
|Others parts numbering|
|LTC4020EUHFPBF: IC BATT CHARGER 55V BB 38QFN|
|DEMO MANUAL DC2044A LTC4020EUHF High Voltage Buck-Boost Multi-Chemistry Battery Charger Description
Demonstration circuit a 55V buck-boost multichemistry battery charger featuring the LTC4020. The board will accept an input voltage between 15V and 55V. The float voltage of the battery output (BAT) is 25.2V, with 3.3A maximum charge current. The converter output (VOUT) has a voltage range to 28V, with 3A maximum load current. The LTC4020 contains a high efficiency synchronous buck-boost DC/DC controller and uses a proprietary average current mode architecture. The LTC4020 battery charger can provide a constantcurrent/constant-voltage charge algorithm (CC/CV, with MODE pin grounded), constant-current charging (CC, with MODE pin floated), or charging with an optimized 4-step, 3-stage lead-acid battery charge profile (connect MODE pin to INTVCC, with a 0 jumper at the optional R29 position). The LTC4020 data sheet gives a complete description of the IC operation and application information. The data sheet must be read in conjunction with this quick start guide. Design files for this circuit board are available at http://www.linear.com/demo/DC2044A
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SYMBOL Input Voltage Range Battery Float Voltage (BAT) (Nominal) Converter Output Voltage (VOUT) Maximum Battery Charge Current, IBAT Maximum Converter Output Current, IOUT Typical Efficiency Typical Converter Output Ripple
CONDITIONS IBAT to 3.3A IOUT to 3A IOUT = 0A IBAT = 0A VIN = 24V, VOUT = 25.2V, IOUT = 3A VIN = 55V, VOUT = 25.2V, IOUT 3A (20MHz BW)
Demonstration circuit 2044A is easy to set up to evaluate the performance of the LTC4020. Refer to Figure 1 for the proper measurement equipment setup and follow the procedure below: 1.With power off, connect the input power supply (set for 0V) to VIN and GND (input return). 2.Connect the converter output load between VOUT and GND (Initial load: no load). 3.Connect the DVMs to the input and outputs. 4.Turn on the input power supply and slowly increase to 24V. Check for the proper output voltages, VOUT of 25.2V and BAT 25.2V. 5.Once the proper output voltages are established, adjust the converter output load within the operating range (3A maximum) and/or adjust input voltage to 55V) and observe the output voltage regulation, ripple voltage, efficiency and other parameters. Note: When measuring the output or input voltage ripple, do not use the long ground lead on the oscilloscope probe. See Figure 2 for the proper scope probe technique. Short, stiff leads need to be soldered to the and terminals of an output capacitor. The probe's ground ring needs to touch the lead and the probe tip needs to touch the lead. Additional Notes: 1. CAUTION: Be careful when testing with high voltage. High voltage can result in an electric shock if care is not taken. 2. CAUTION: Batteries are potentially dangerous high energy sources. Improper connection, overcharge, or rapid discharge could result in explosion and/or file. Please read the specification/manual of the battery before test. 3. The combined converter output load current and battery charging current should not exceed 3.3A. 4. Without a proper battery, BAT output can be open or connected with other suitable loads for test purposes. It may be a good practice to add low ESR electrolytic capacitors to the BAT output at 35V, for 25.2V float voltage). Note: These capacitors help simulate the low impedance of a battery and maintain stability of the charge current loop. It's only needed for test purposes with electronic or resistive loads, and not needed in the actual battery application/test (where the BAT load is a battery). 5. BAT float voltage can be easily adjusted with the resistor divider R8/R10. Converter output voltage VOUT can be adjusted with the resistor divider R9/R11. Adjust/ optimize the loop compensations if necessary.
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