LT8705 automatic step-up and down-voltage, solar maximum power tracking (MPPT), battery charge controller, can provide efficient and stable power supply for various devices (such as notebooks).
1. Module size: 125*76*25
2. Linear Technology LT8705 synchronous rectifier automatic buck-boost control scheme
3. Non-isolated BUCK-BOOST
4. Current mode control (see the difference between current mode and voltage module, the former is better than the latter)
5. Input voltage 2.8-100V (2.8V work requires an external EXTVCC (>6.5V)
6. Adjustable input voltage range: 9-80V This function is suitable for MPPT solar panels, please see the detailed instructions.
7. Output voltage adjustment: 1.3-80V (adjustable resistors need to be replaced or connected resistors, please reserve a certain margin)
8. Output current adjustment: 0.5-15A
Application note
1. Solar maximum power charging: The input current limit function is very suitable for solar panel constant current source charging. It is a good choice to purchase two 200W battery panels and charge the module. The output is directly connected to the battery for charging, no need to worry about reverse irrigation, just output The positive and negative of the battery are not reversed.
2. Car battery high-current and high-efficiency charging, car two-stage battery charging power supply system
3. Large-capacity lithium battery, iron-lithium battery, high current constant current charging
4. High-power LED constant current drive
5. Battery regulated power supply system, backup regulator for telecommunication base station.
6. It can be used as a less demanding adjustable voltage stabilizer source (response speed, accuracy, and noise are not as good as linear voltage stabilizers, but have high efficiency and high power characteristics)
7. Other adjustable constant current applications
other
The difference between DC-DC controller current mode and voltage mode:
Voltage mode: There is only one voltage feedback loop, and the PWM is changed after the voltage signal is transformed. The dynamic response is poor and a larger filter capacitor is required. The system does not have a built-in current-limiting protection function, some of which may be external and do not participate in system feedback.
Current mode: fast dynamic response, good stability, real soft start of inductor current, accurate and fast current feedback, easy to realize current sharing; easy feedback design; relatively low requirement on capacitance; this mode uses inductor current signal as feedback inner loop, plus The upper voltage feedback is dual-loop control of the outer loop.
MPPT function: The module has an input voltage limit function, that is, after setting the solar maximum power point voltage, as long as the voltage is lower than this value, the module will reduce the output current, reduce the output power, and ensure that the input voltage is stable at the set value. For example, the maximum power point voltage of the solar cell is 34V, first adjust the input voltage to 34V, and adjust the input voltage potentiometer counterclockwise until the module has no output. At this time, the maximum input voltage of the module is 34V.
Compared with the general solar controller without MPPT function, the energy utilization rate of this module is still much higher, at least under the maximum light conditions.
Mode selection: This module provides mode selection, which can be selected in skip mode, discontinuous mode, and forced continuous mode.