Automatic power monitor (APM) in switching charger with smooth transition loop selector (STLS) for high-energy throughput system

Tsai, Tsu-Wei; Peng, Ruei-Hong; Su, Yu T.; Chen, Yaping; Chen, Ke-Horng; Wang, Shih-Ming; Lee, Ming-Wei; Luo, Hsin-Yu

doi:10.1109/ecce.2012.6342505

Cited by 2 publications

(2 citation statements)

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“…6 shows the basic structure and concept of the proposed AMDU circuit, which is composed of two V-to-I converters (VI 1 and VI 2 ), one comparator, and one switch MOSFET M SW . VI 1 translates V 1 to K 1 I 1 to charge C 1 for getting the charging slope m 1 in (7). Similarly, VI 2 translates V 2 to K 2 I 2 to charge C 2 for getting another charging slope m 2 in (7).…”

Section: B Subtraction Sample-and-hold (S/h)mentioning

confidence: 97%

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Switching-based charger with continuously built-in resistor detector (CBIRD) and analog multiplication-division unit (AMDU) for fast charging in Li-Ion battery

Peng

Tsai

Chen

et al. 2013

2013 Proceedings of the ESSCIRC (ESSCIRC)

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proposed continuously built-in resistor detector (CBIRD) monitors the built-in resistance (BIR) of the Li-Ion batteries for achieving fast charging process. Owing to the detection of the battery built-in resistance in real-time, the transition from the constant-current (CC) mode to the constantvoltage (CV) mode can be postponed to have large energy storing in the battery, Thus, the charging time of the switching-based charger can be effectively reduced. The CBIRD is composed of four analog circuits, which are the differentiator, the subtraction sample-and-hole (S/H), analog multiplication-division unit (AMDU), and voltage adder for accurate BIR detection. Thus, the proposed switching-based charger with the CBIRD has 45% charging time improvement for Li-ion batteries. Keywords-Switching-based charger, constant-current mode (CC), constant-voltage (CV) mode, built-in resistor (BIR), continuously built-in resistor detector (CBIRD), analog multiplication-division unit (AMDU) I INTRODUCTIONNowadays, Lithium-ion (Li-Ion) batteries are widely used in portable electronics such as smart phones, tablet PCs, laptops and digital cameras due to its small size, large capacity and recharging ability. The battery chargers with no matter low drop-out (LDO) -based or switching-based method become more and more popular products. LDO-based charger has the advantage of ripple-free, compact and high accuracy [1]-[2] but suffers from low efficiency when charging with large drop-out voltage. In contrast, switching-based charger is able to guarantee high efficiency [3] and provides higher current capability to accelerate charging process.Here, a switching-based charger with the typical charging topology is adopted [4] for charging the Li-Ion battery; it includes trickle current (TC) mode, constant-current (CC) mode and constant-voltage (CV) mode. The TC mode operates in small charging current for protecting the battery in low battery capacity; the CC mode is the main charging state with a large charging current for storing energy to the battery rapidly. When the battery voltage is close to the target voltage V FULL , to protect battery from overcharge, the charger will turn into the CV mode to lower down the charging current for ensuring the battery to be charged to an appropriate rated voltage. Fig. 1 depicted the charging profile with the built-in resistance (BIR) effect. The Li-ion battery can be modeled as a BIR and a very large capacitor. The battery voltage V BAT is the sum of the voltage across the build-in resistance and the voltage stored in the capacitor V BATO , which represents the energy stored in the battery. The BIR in battery packs, which may vary from 150mΩ to 300mΩ according to different types of the Liion battery, causes the difference between the sensed voltage V BAT and the actual stored voltage V BATO . The BIR generates the voltage drop while the charging current flowing through it. It makes the charger transit from the CC mode to the CV mode too early (TP1). Unfortunately, the charging time is extended due to low c...

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Section: B Subtraction Sample-and-hold (S/h)mentioning

confidence: 97%

“…The switching-based charger consists of three parallel loops (TC, CC, and CV) to fulfill the complete charging process. The smooth transition loop selector (STLS) [7] helps the charger smoothly determine the correct loop. The shared error amplifier can avoid using three sets of compensation networks for different loops.…”

Section: Introductionmentioning

confidence: 99%