参数资料
| 型号： | LTC4100EG#TR |
| 厂商： | Linear Technology |
| 文件页数： | 23/30页 |
| 文件大小： | 0K |
| 描述： | IC CHARGER SMART BATTERY 24-SSOP |
| 标准包装： | 1,800 |
| 功能： | 充电管理 |
| 电池化学： | 智能电池 |
| 电源电压： | 6 V ~ 28 V |
| 工作温度： | -40°C ~ 85°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 24-SSOP（0.209"，5.30mm 宽） |
| 供应商设备封装： | 24-SSOP |
| 包装： | 带卷 (TR) |
第1页第2页第3页第4页第5页第6页第7页第8页第9页第10页第11页第12页第13页第14页第15页第16页第17页第18页第19页第20页第21页第22页当前第23页第24页第25页第26页第27页第28页第29页第30页
LTC4100
APPLICATIONS INFORMATION
The MOSFET power dissipations at maximum output
current are given by:
PMAIN = V OUT /V IN (I MAX ) 2 (1 + δ ?T)R DS(ON)
+ k(V IN ) 2 (I MAX )(C RSS )(f OSC )
PSYNC = (V IN – V OUT )/V IN (I MAX ) 2 (1 + δ ?T)R DS(ON)
where δ ?T is the temperature dependency of R DS(ON) and
k is a constant inversely related to the gate drive current.
Both MOSFETs have I 2 R losses while the PMAIN equation
includes an additional term for transition losses, which
are highest at high input voltages. For V IN < 20V the high
current efficiency generally improves with larger MOSFETs,
while for V IN > 20V the transition losses rapidly increase to
the point that the use of a higher R DS(ON) device with lower
C RSS actually provides higher efficiency. The synchronous
MOSFET losses are greatest at high input voltage or during
a short circuit when the duty cycle in this switch in nearly
100%. The term (1 + δ ?T) is generally given for a MOSFET
in the form of a normalized R DS(ON) vs temperature curve,
but δ = 0.005/°C can be used as an approximation for low
voltage MOSFETs. C RSS = Q GD /?V DS is usually specified
in the MOSFET characteristics. The constant k = 2 can be
used to estimate the contributions of the two terms in the
main switch dissipation equation.
If the charger is to operate in low dropout mode or with
a high duty cycle greater than 85%, then the topside
P-channel efficiency generally improves with a larger
MOSFET. Using asymmetrical MOSFETs may achieve cost
savings or efficiency gains.
The Schottky diode D1, shown in the typical application
on the back page, conducts during the dead-time between
the conduction of the two power MOSFETs. This prevents
the body diode of the bottom MOSFET from turning on
and storing charge during the dead-time, which could cost
as much as 1% in efficiency. A 1A Schottky is generally
a good size for 4A regulators due to the relatively small
average current. Larger diodes can result in additional
transition losses due to their larger junction capacitance.
The diode may be omitted if the efficiency loss can be
tolerated.
Calculating IC Power Dissipation
The power dissipation of the LTC4100 is dependent upon
the gate charge of the top and bottom MOSFETs (Q2 &
Q3 respectively) The gate charge (QG) is determined from
the manufacturer’s data sheet and is dependent upon both
the gate voltage swing and the drain voltage swing of the
MOSFET. Use 6V for the gate voltage swing and V DCIN for
the drain voltage swing.
PD = V DCIN ? ( f OSC (QG Q2 + QG Q3 ) + I DCIN ) + V DD ? I DD
Example: V DCIN = 19V, f OSC = 345kHz, QG Q2 = 25nC,
QG Q3 = 15nC, I DCIN = 5mA, V DD = 5.5V,
I DD = 1mA.
PD = 428mW
Calculating V DD Current
The LTC4100 V DD current, or I DD , consist of three parts:
a. I RUN = Current due to active clocking and bias inside
the IC.
b. I THRM = Current due to thermistor circuit activity.
c. I ACCEL = Current due to SMBus acceleration activity.
I DD = I RUN + I THRM + I ACCEL
a) I RUN current is basically independent of SCL clock rate.
Once the LTC4100 determines that there is activity on
the SMBus, it turns on its internal HF oscillator. This
HF oscillator remains on until a stop event occurs or
SDA and SCL are at logic level 1 for the SMBus timeout
period. Then it shuts off the HF oscillator. Thus, the
length of the transmission and the rate of transmission
bursts are more important in determining how much
current the LTC4100 burns, rather than the SCL rate.
In the equation below, I Q is the static current the IC
consumes as a function of the V DD voltage when not
active. Since it is hard to quantify the actual messages
going down the SMBus, one must estimate the SMBus
activity level in term of bus utilization per second.
I RUN = Message Duty Cycle ? 950μ A
+ (1 – Message Duty Cycle ) ? I Q
where I Q (typical) = V DD /47.2k
23
For more information www.linear.com/LTC4100
4100fc
相关PDF资料 |
PDF描述 |
|---|---|
| LTC4101EG#PBF | IC CNTRLR BATT CHRG 24-SSOP |
| LTC4110EUHF#TRPBF | IC BATTERY BACKUP MANAGER 38-QFN |
| LTC4150IMS#TRPBF | IC COUNTER/GAUGE GAS/BATT 10MSOP |
| LTC4155IUFD#TRPBF | IC I2C POWER MANAGER DUAL 28QFN |
| LTC4160EUDC-1#TRPBF | IC SWITCH POWER MANAGER 20-QFN |
相关代理商/技术参数 |
参数描述 |
|---|---|
| LTC4100EGTRPBF | 制造商:LINER 制造商全称:Linear Technology 功能描述:Smart Battery Charger Controller |
| LTC4101 | 制造商:LINER 制造商全称:Linear Technology 功能描述:Smart Battery Charger Controller |
| LTC4101EG | 制造商:LINER 制造商全称:Linear Technology 功能描述:Smart Battery Charger Controller |
| LTC4101EG#PBF | 功能描述:IC CNTRLR BATT CHRG 24-SSOP RoHS:是 类别:集成电路 (IC) >> PMIC - 电池管理 系列:- 产品培训模块:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 标准包装:2,500 系列:- 功能:电池监控器 电池化学:碱性，锂离子，镍镉，镍金属氢化物 电源电压:1 V ~ 5.5 V 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:SOT-23-6 供应商设备封装:SOT-6 包装:带卷 (TR) |
| LTC4101EG#TRPBF | 功能描述:IC CNTRLR BATT CHRG 24-SSOP RoHS:是 类别:集成电路 (IC) >> PMIC - 电池管理 系列:- 产品培训模块:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 标准包装:2,500 系列:- 功能:电池监控器 电池化学:碱性，锂离子，镍镉，镍金属氢化物 电源电压:1 V ~ 5.5 V 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:SOT-23-6 供应商设备封装:SOT-6 包装:带卷 (TR) |
发布紧急采购，3分钟左右您将得到回复。