 |
|
| If you can't view the Datasheet, Please click here to try to view without PDF Reader . |
|
|
|
| If you can't view the Datasheet, Please click here to try to view without PDF Reader . |
|
|
| Datasheet File OCR Text: |
| ace 4054 c 500ma/1.5a standalone linear li - ion battery charge ver 1. 2 1 d escription the ace4054 c is a single cell, fully integrated constant current (cc) / constant voltage (cv) li - ion battery charger. its compact package with minimum external components requirement makes the ace4054 c ideal for portable applications. no exter nal sense resistor or blocking diode is necessary for the ace4054 c . build - in thermal feedback mechanism regulates the charge current to control the die temperature during high power operation or at elevated ambient temperature. the ace4054 c has a pre - charg e function for trickle charging deeply discharged batteries. the fast charge current can be programmed by an external resistor. cv regulation mode is automatically enabled once the batterys charging curve reaches the constant voltage portion. the output c urrent then decays and is finally terminated once the charge current drops to 1/10 th of the programmed value. the ace4054 c keeps monitoring the battery voltage and enables a new charge cycle once the voltage drops by 150mv below the cv value. power supply state is constantly monitored and the battery drain current is reduced to minimum value automatically when the ace4054 c sense s a lack of input power. in its shutdown mode, the ace4054 c can reduce the supply current to less than 25a. a status pin outputs a logic high/low to indicate the charging status and the presence of power supply. other features include charge current monitor, under - voltage lockout. features ? s tandalone capability with no requirement of external mosfet, s ense resistor or blocking diode ? complete linear charger in compact package for si ngle cell lithium - ion batteries ? programmable pre - charge, fast charge and termination current ? constant - current/constant - voltage operation with thermal reg ulation to maximize charge rate without risk of overh eating ? charges single cell li - ion batteries directly from usb port ? preset 4.2v charge voltage with 1% accuracy ? automatic recharge ? charge status output pin ? c/10 charge termination ? 2 5a supply current in shutdown ? 2.9v trickle charge threshold ? s oft - start limits inrush current application ? cellu lar telephones,pdas,mp3 players ? charging docks and cradles ? bluetooth applications
ace4054 c 500ma/1.5a standalone linear li - ion battery charge ver 1. 2 2 absolute maximum ratings parameter max unit vcc - 0.3 ~ 6.5 v prog - 0.3 ~ vcc+0.3 v bat - 0.3 ~ 5 v chrg - 0.3 ~ 6.5 v bat short - circuit duration continuous prog pin current 2 m a maximum junction temperature 125 operating ambient temperature range - 40 ~ 85 storage temperat ure range - 40 ~ 125 note: exceed these limits to damage to the device. exposure to absolute maximum rating conditions may affect device reliability. packaging type sot - 23 - 6 esop - 8 6 5 4 1 8 2 7 3 6 4 5 1 2 3 pin description chrg: open - drain charge status output. the chrg pin outputs low when the battery is charging. stdby: open - drain charge status output. the stdby pin outputs lo w when the battery is full. gnd: ground. bat: charge current output. this pin provides charge current to the battery and regulates the final float voltage to 4.2v which is set by an internal precision resistor divider. vcc: positive input supply. needs to be bypassed with at least a 1 f capacitor. when input voltage drops to within 30mv of the bat pin voltage, the ace4054 c switches to shutdown mode. prog: program, monitor the charge current and shutdown. this pin set to 1v in constant - current mode. the charge current is programmed by connecting a 1% resistor, rprog, to gnd pin. the charge current can be calculated using the following formula: i bat =(v prog /r prog )*1000 sot - 23 - 6 esop - 8 description 1 7 chrg 2 3 gnd 3 5 bat 4 4 vcc 5 6 stdby 6 2 prog 1.8 nc ace4054 c 500ma/1.5a standalone linear li - ion battery charge ver 1. 2 3 the prog pin can also be used to switch the charger to shutdown mode by disconnecting the program resistor from gro und. this results in a 3 a current to pull the prog pin to a high level shutdown threshold voltage, thus stop the charging and reduce the supply current to 25a. this pin is also clamped to approximately 2.4v. a higher voltage beyond this value will draw currents as high as 1.5ma . device normal operation can be resumed by reconnecting the rprog resistor to ground. ordering information ace4054 c xx + h block diagram pb - free gm : sot - 23 - 6 im : esop - 8 halogen - free ace4054 c 500ma/1.5a standalone linear li - ion battery charge ver 1. 2 4 electrical characteristics v cc =5v,t a =25 , r prog =10k, unless otherwise n ote. parameter symbol conditions min typ max units input supply voltage v cc 4.25 6.0 v input supply current i cc charge mode(note 2 ) 300 2000 a standby mode (charge terminated) 200 500 a shutdown mode (r prog not connected, v cc ace4054 c 500ma/1.5a standalone linear li - ion battery charge ver 1. 2 6 typical characteristic (v cc =5v,t a =25 , unless otherwise noted ) ace4054 c 500ma/1.5a standalone linear li - ion battery charge ver 1. 2 7 typical characteristic (v cc =5v,t a =25 , unless otherwise noted ) ace4054 c 500ma/1.5a standalone linear li - ion battery charge ver 1. 2 8 detailed description the ace4054 c is a single cell, fully integrated constant current(cc) /constant voltage (cv) li - ion battery charger. it can deliver up to 1.5a of charge current with a final float voltage accuracy of ace4054 c has a build - in thermal regulation circuitry that ensures its safe operation. no blocking diode or external current sense resistor is required; hence reduce the external components for a basic charger circuit to two. the ace4054 c is also capab le of operating from a usb power source. n ormal c harge c ycle the ace4054 c initiates a charge cycle once the voltage at the vcc pin rises above the uvlo threshold level. a 1% precision resistor needs to be connected from the prog pin to ground. if the volt age at the bat pin is less than 2.9v, the charger enters trickle charge mode. in this mode, the charge current is reduced to nearly 1/10 the programmed value until the battery voltage is raised to a safe level for full current charging. the charger switch es to constant - current mode as the bat pin voltage rises above 2.9v, the charge current is thus resumed to full programmed value. when the final float voltage (4.2v) is reached, the ace4054 c enters constant - voltage mode and the charge current begins to decre ase until it drops to 1/10 of the preset value and ends the charge cycle. p rogramming c harge c urrent the charge current is programmable by setting the value of a precision resistor connected from the prog pin to ground. the charge current is 1000 times o f the current out of the prog pin. the program resistor and the charge current are calculated using the following equations: r prog = 1000v/i chg the charge current out of the bat pin can be determined at any time by monitoring the prog pin voltage using th e following equation: i bat =(v prog /r porg )*1000 ace4054 c has a self - temperature - limiting (stl) function, the chip starts to limit its charge current by reducing vprog gradually after silicon temperature rises above 70 and ambient ace4054 c would have the same charge current and junction temperature as chips without stl function at room temperature. as the ambient temperature ace4054 c would reduce its charge current and hence the junction temperature would be much lower. the stl function helps to improve system reliability. c harge t ermination the ace4054 c ke eps monitoring the prog pin during the charging process. it terminates the charge cycle when the charge current falls to 1/10th the programmed value after the final float voltage is reached. when the prog pin voltage falls below 100mv for longer than tterm (typically 1ms), charging is terminated. the charge current is latched off and the ace4054 c enters standby mode, where the input supply current drops to 200 a. (note: c/10 termination is disabled in trickle charging and thermal limiting modes). ace4054 c 500ma/1.5a standalone linear li - ion battery charge ver 1. 2 9 during charging, the transient response of the circuit can cause the prog pin to fall below 100mv temporarily before the battery is fully charged, thus can cause a pr emature termination of the charge cycle. a 1ms filter time (tterm) on the termination comparator can prevent this from happening. once the average charge current drops below 1/10th the programmed value, the ace4054 c terminates the charge cycle and ceases to provide any current through the bat pin. in this state, all loads on the bat pin must be supplied by the battery. the ace4054 c constantly monitors the bat pin voltage in standby mode and resume another charge cycle if this voltage drops below the recharge threshold (vrechrg). user can also manually restart a charge cycle in standby mode either by removing and then reapplied the input voltage or restart the charger using the prog pin. a diagram of typical charge cycle is shown in figure 1. figure 1. charge cycle diagram charge status indicator (chrg) there are two different states of the charge status output, namely pull - down and high impedance. the pull - down state indicates that the ace4054 c is in a charge cycle. when the charge cycle has terminated, the pin state is then determined by undervoltage lockout conditions. if the difference between vcc and bat pin voltage is less than 100mv or insufficient voltage is applied to the vcc pin, high impedance appears on the charge statues pin. ace4054 c 500ma/1.5a standalone linear li - ion battery charge ver 1. 2 10 t hermal l imiting build - in feedback circuitry mechanism can reduce the value of the programmed charge current once the die temperature tends to rise above 120c, hence prevents the temperature from further increase and ensure device safe operation. u nder voltage l ockout (uvlo) build - in undervoltage lockout circuit monitors the input voltage and keeps the charger in shutdown mode until vcc rises above the undervoltage lockout threshold. the uvlo circuit has a built - in hysteresis of 200mv. furthermore, to p rotect against reverse current in the power mosfet, the uvlo circuit keeps the charger in shutdown mode if vcc falls to within 30mv of the battery voltage. if the uvlo comparator is tripped, the charger will not come out of shutdown mode until vcc rises 10 0mv above the battery voltage. m anual s hutdown floating the prog pin by removing the resistor from prog pin to ground can put the device in shutdown mode. the battery drain current is thus reduced to less than 5a and the supply current to less than 50 a. reconnecting the resistor back will restart a new charge cycle. the chrg pin is in a high impedance state if the ace4054 c is in undervoltage lockout mode. a utomatic r echarge after the termination of the charge cycle, the ace4054 c constantly monitors the bat pin voltage and starts a new charge cycle when the battery voltage falls below 4.05v, keeping the battery at fully charged condition. chrg output enters a pull - down state during recharge cycles. a pplications i nformation s t a b i l i t y c o n s i d e r a t i o n s when a battery is connected to the output, the constant - voltage mode feedback is always stable. however, in the case of absence of battery, an output capacitor is recommended to reduce ripple voltage. in the case of high value capacitance or low esr ceramic capacitors, a small value series resistor (~1 recommended. no series resistor is needed if tantalum capacitors are used. in constant - current mode, the prog pin is in the feedback loop, thus its impedance affects the stability. the maximum allowed value of the program resistor is 20k, and additional capacitance reduces this value. the pole frequency at the prog pin needs to be kept above 100khz to maintain device stability. therefore, the maximum resistance value can be calculated from the following equation, cprog is the capacitance loaded to the prog pin average rather than instantaneous charge current is more of a concern. a simple low pass filter can be used on the prog pin to measure the average battery current as shown in figure 2. a 10k resistor has been added between the prog pin and the filter capacitor to ensure stability. ace4054 c 500ma/1.5a standalone linear li - ion battery charge ver 1. 2 11 ace4054 c figure 2. isolating capacitive load on prog pin and filtering p o w e r d i s s i p a t i o n the power dissipated in the ic causes the rise of d ie temperature. most of the power dissipation is caused by the internal power mosfet, and can be calculated by the following equation: p d =(v cc - v bat )*i bat where pd is the power dissipated, vcc is the input supply voltage, vbat is the battery voltage and ibat is the charge current. the approximate ambient temperature at which the thermal feedback begins to protect the ic is: t a =120 - p d ja t a =120 - (v cc - v bat )*i bat * ja example: an ace4054 c operating fro m a 5v usb supply is programmed to supply 400ma full - scale current to a discharged li - ion bat tery with a voltage of 3.75v. assuming ja is 150 c /w (see board layout considerations), the ambient temperature at which the ace4054 c will begin to reduce the char ge current is approximately: t a =120 - (5v - 3.75v)*(400ma) *150 /w t a =120 - 0.5w*150 /w=120 - 75 t a =45 the ace4054 c can be used above 45 c ambient, but t he charge current will be reduced from 400ma. the approximate current at a given ambient temperature can be approximated by: using the previous example with an ambient temperature of 60 c, the charge current will be reduced to approximately: moreover, when thermal feedback reduces the charge current, the voltage at the prog pin is also reduced proportionally as di scussed in the operation section. it is important to remember that ace4054 c applications do not need to be designed for worst - case thermal conditions since the ic will automatically reduce power dissipation when the junction temperature reaches approximatel y 120 c. ace4054 c 500ma/1.5a standalone linear li - ion battery charge ver 1. 2 12 t h e r m a l c o n s i d e r a t i o n s due to its compact size, it is of great importance to use a good thermal pc board. good thermal conduction increases maximum allowed charge current value. the thermal path for the heat generated by the ic is from the die to the copper lead frame, through the package leads, (especially the ground lead) to the pc board copper. the pc board copper is the heat sink. the footprint copper pads should be as wide as possible and expand out to larger copper areas to spread and dissipa te the heat to the surrounding ambient. feed through vias to inner or backside copper layers are also useful in improving the overall thermal performance of the charger. other heat sources on the board, not related to the charger, must also be considered w hen designing a pc board layout because they will affect overall temperature rise and the maximum charge current. i n c r e a s i n g t h e r m a l r e g u l a t i o n c u r r e n t reducing the voltage drop across the internal mosfet can significantly decrease the power dissipation i n the ic. minimized power dissipation results in reduced die temperature rise and hence equivalent increased charge current in thermal regulation. one way is to bypass some of the current through an external component, such as a resistor or diode. example: an ace4054 c operating from a 5v wall adapter is programmed to supply 600ma full - scale current to a discharged li - ion battery with a voltage of 3.75v. assuming ja i s 125c /w, the approximate charge current at an ambient temperature o f 25 c is: by dropping voltage across a resistor in series with a 5v wall adapter (shown in figure 3), the on - chip power dissipation can be decreased, thus increasing the thermally regulated charge current ace4054 c figure 3. a circuit to maximize thermal mode charge current v c c b y p a s s c a p a c i t o r due to their self - resonant and high q characteristics, some types of ceramic capacitors can cause high voltage transients under some start - up conditions (i.e connecting the charger input to a live power source). adding a small value resistor in series wi th the ceramic capacitor can minimize start - up voltage transients ace4054 c 500ma/1.5a standalone linear li - ion battery charge ver 1. 2 13 c h a r g e c u r r e n t s o f t - s t a r t to avoid the start - up transients, a soft - start circuit is included to ramp the charge current from zero to programmed value over a period of time. this has the ef fect of minimizing the transient current load on the power supply during start - up. packing information sot - 23 - 6 ace4054 c 500ma/1.5a standalone linear li - ion battery charge ver 1. 2 14 pa cking information esop - 8 heat slug (btm) notes: all dimensions refer to jedec standard ms - 012 aa d o not include mold flash or protrusions. b ase metal section b - b ace4054 c 500ma/1.5a standalone linear li - ion battery charge ver 1. 2 15 notes ace does not assume any responsibility for use as critical components in life support devices or systems without the express written approval of the president and general counsel of ace electronics co., ltd. as sued herein: 1. life support devices or systems are devices or systems which, (a) are intended for surgical implant into the body, or (b) support or sustain life, an d shoes failure to perform when properly used in accordance with instructions for use provided in the labeling, can be reasonably expected to result in a significant injury to the user. 2. a critical component is any component of a life support device or syst em whose failure to perform can be reasonably expected to cause the failure of the life support device or system, or to affect its safety or effectiveness. ace technology co., ltd. http://www.ace - ele.com/ |
Price & Availability of ACE4054C
 |
|
|
|
|
All Rights Reserved © IC-ON-LINE 2003 - 2022 |
| [Add Bookmark] [Contact Us] [Link exchange] [Privacy policy] |
|
Mirror Sites : [www.datasheet.hk]
[www.maxim4u.com] [www.ic-on-line.cn]
[www.ic-on-line.com] [www.ic-on-line.net]
[www.alldatasheet.com.cn]
[www.gdcy.com]
[www.gdcy.net] |