Power path management devices in the system can be simultaneously powered battery charger(a)
Lithium-ion sony laptop battery because of weight and capacity at both higher energy density, it is widely used in portable devices. The use of smart phones, PDA and MP3 player and other equipment at the user wants without the use of the battery case, through the input power supply for the equipment. This requires a kind of known as the "power path management" architecture of power in order to separate the path separately for equipment supply and battery charging system.
Dynamic power path management (DPPM) sony pcga-bp1n, sony pcga-bp2ny battery charger
The most commonly used in battery charging and system power supply configuration, the system load can be directly connected to the battery charger output. While this architecture is not only easy-to-use and lower cost, but because of the invalidity of the battery charge current control may lead to abnormal termination and charging safety timer False Alarm.
dppm bq2403x series sony pcga-bp2r, sony pcga-bp2s battery charger has a power-sharing function, the system can be simultaneously powered battery charger. This avoids the end-of-charge timer and security issues with a view to minimize the AC adapter's rated power and increased system stability. This feature also allows the system to excessive battery discharge, while a normal job.
Battery charger power path management structure diagram shown in Figure 1. When the AC adapter when connected to power supply, MOSFET Q1 on the system bus voltage VOUT pre-regulator, the value is higher than the maximum value of the battery voltage regulator VBAT. This adapter has established a system input with the direct path. MOSFET Q2 dedicated to battery charging, so non-interfering with the system sony pcga-bp2t, sony pcga-bp2v battery. When connected to and select USB when, MOSFET Q3 all open, Q3 output with USB output almost equivalent output voltage of the MOSFET Q2 to control the battery charging.
Figure 1 battery charger power path management structure diagram
Dppm dynamically monitor the system bus voltage. If the adapter or USB because of the input current caused by the smaller system bus voltage down to preset values, the battery charge current will be reduced until the output voltage stop the decline. Dppm control only as far as possible in a steady-state conditions, the system in order to obtain the required current, and use the remaining battery charge current. For this reason, power adapters are designed based on the system, rather than the maximum peak power system. This allows designers to use smaller rated power and lower cost adapters.
Dppm typical application circuit shown in Figure 2. When the system with the sony pcga-bp4v, sony pcga-bp71 battery charger current total of more than AC adapter or USB current limit, and the system bus connected to the capacitor, has begun to discharge, and the system bus voltage decreases have also begun. When the system bus voltage down to the target set dppm pin threshold, reducing the charge current to prevent overload by AC adapter and lead to system crashes. If the charge current dropped to 0 A when still unable to maintain the system bus voltage, the battery will be temporarily discharge, power supply to the system in order to prevent system crashes. This is the "battery supplementary mode", Figure 3 for the model with experimental waveforms dppm work.