- 您现在的位置：买卖IC网 > PDF目录97840 > 74LV4799PWDH-T (NXP SEMICONDUCTORS) 1-CHANNEL POWER SUPPLY SUPPORT CKT, PDSO16 PDF资料下载
参数资料
| 型号： | 74LV4799PWDH-T |
| 厂商： | NXP SEMICONDUCTORS |
| 元件分类： | 电源管理 |
| 英文描述： | 1-CHANNEL POWER SUPPLY SUPPORT CKT, PDSO16 |
| 文件页数： | 13/18页 |
| 文件大小： | 179K |
| 代理商： | 74LV4799PWDH-T |
Philips Semiconductors
Product specification
74LV4799
Timer for NiCd and NiMH chargers
1998 Apr 20
4
PIN DESCRIPTION
PIN NO.
SYMBOL
NAME AND FUNCTION
1
LED
LED driver output pin (active LOW)
2
EN
Enable output (active HIGH)
3
EN
Enable output (active LOW)
4
Vin
External power input
5
PWRS
Power sense input
6
MOLLI/SCO
More-or-less-low-indication output (active LOW)/scan test output
7
SEL
LED mode select input
8
GND
Ground (0 V)
9
DIS
Discharge input (active LOW)
10
RC
External resistor pin 3-State oscillator output (charge)
11
RD
External resistor pin 3-State output (discharge)
12
RS
External resistor pin 3-State output (self-discharge)
13
IOSC
Oscillator input
14
SCAN
Scan test mode select input (active HIGH)
15
SCI
Scan test input
16
VCC
Positive supply voltage
Power On Reset.
An automatic Power On Reset initiates the IC when the battery is
discharged and power is connected to the circuit. The initial
condition is the charge mode in which the counter is reset and
counts from zero up to maximum. At start up, the battery therefore
always receives a full charge cycle. When a partially charged battery
is inserted, it may be over-charged during the first cycle. To guard
against this, simply replace the resistor at the RC pin with an NTC
type which is in good thermal contact with the battery. If the
temperature of the battery increases, the frequency of the oscillator
also increases to quickly reach a counter full indication and
switch-over to trickle charge. With a battery that is almost
completely discharged, the POR input can also be activated during
discharge or self-discharge. The counter will then be reset to zero.
This is a correct action while returning to the initial condition.
Power-on sensing.
Because this IC supports virtually all battery chargers, the PWRS input
has a broad input frequency spectrum (active HIGH to 100 kHz). A
pull-down circuit at the PWRS input allows detection of the open state
which corresponds to an inactive charger. A HIGH level on the PWRS
input, or an AC signal up to 100 kHz, enables the charge mode.
Start-up with low battery voltage.
Good start-up, even with an un-charged battery, is assured by using
the VIN input. The voltage on the VIN input biases the external
bipolar transistors at the EN or EN output, even if the IC is not yet
functioning. After the battery has received sufficient charge, the
internal control logic takes over control of the EN and EN outputs.
Charge mode.
This mode is selected when PWRS is active (HIGH or pulsed) and
the discharge input DIS is HIGH. The EN output is HIGH, and the
EN output is LOW initiating continuous charge of the battery. The
counter then counts from the zero state up to the maximum value.
The clock frequency is determined by the external capacitor and
resistor connected to the RC output. The counter stops when it
reaches its maximum value and the EN and EN outputs switch over
from the continuous charge to the trickle charge mode.
Trickle charge mode.
At the maximum counter value, it is assumed that the battery is fully
charged. The counter stops and remains on this maximum value.
The EN and EN outputs switch over from the continues charge to
the trickle charge mode. In the trickle charge mode, the average
charge current is reduced to only compensate the self-discharge of
the battery by using the dedicated duty cycle control. The control is
dedicated because it adjusts the duty cycle in inverse proportion to
the load current, resulting in a fixed charger current irrespective of
the kind of charger (e.g. 4-hour or 16-hour charger). In the trickle
charge mode, the oscillator circuitry alternately generates 4 periods
of RC -C1 time-constant, and 3 periods of the RS -C1 time-constant
(See Figure 1).
Discharge mode.
The discharge input (DIS) is used to detect the discharge of the
battery. If DIS is LOW, the counter counts down. The clock
frequency is determined by the external capacitor and resistor at the
RD output. If PWRS is inactive (LOW or open), the EN output is
LOW, and the EN output is in the high impedance OFF-state (no
charge of the battery). This is called the discharge mode. If PWRS is
active, the circuit is in the charge/discharge mode.
Charge/Discharge mode.
If DIS is LOW and PWRS is active (HIGH or pulsed), the circuit is in
the charge/discharge mode. The counter counts down. The clock
frequency is determined by the external capacitor and resistor tied
at the RD output. The EN output is HIGH, and the EN output is LOW
initiating continuous charge of the battery. The battery is therefore
charged and discharged at the same instant, thereby maintaining a
better load condition of the battery.
相关PDF资料 |
PDF描述 |
|---|---|
| 74V2G66CTR | DUAL 1-CHANNEL, SGL POLE SGL THROW SWITCH, PDSO8 |
| 74V2T66CTR | DUAL 1-CHANNEL, SGL POLE SGL THROW SWITCH, PDSO8 |
| 7705201FC | 8-CHANNEL, SGL ENDED MULTIPLEXER, CDFP16 |
| 7705201FA | 8-CHANNEL, SGL ENDED MULTIPLEXER, CDFP16 |
| 7705201EA | 8-CHANNEL, SGL ENDED MULTIPLEXER, CDIP16 |
相关代理商/技术参数 |
参数描述 |
|---|---|
| 74LV4799PW-T | 功能描述:计时器和支持产品 3.3V TIMER NICD AND NIMH CHARGER RoHS:否 制造商:Micrel 类型:Standard 封装 / 箱体:SOT-23 内部定时器数量:1 电源电压-最大:18 V 电源电压-最小:2.7 V 最大功率耗散: 最大工作温度:+ 85 C 最小工作温度:- 40 C 封装:Reel |
| 74LV4799SD,118 | 功能描述:IC OSC TIMER CTRL 100KHZ 16SOIC RoHS:是 类别:集成电路 (IC) >> 时钟/计时 - 可编程计时器和振荡器 系列:74LV 产品培训模块:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 标准包装:45 系列:- 类型:温度 - 补偿晶体振荡器（TCXO） 计数:- 频率:25MHz 电源电压:3.135 V ~ 3.465 V 电流 - 电源:1.5mA 工作温度:-40°C ~ 85°C 封装/外壳:16-SOIC（0.295"，7.50mm 宽） 包装:管件 供应商设备封装:16-SOIC W 安装类型:表面贴装 |
| 74LV540A | 制造商:TI 制造商全称:Texas Instruments 功能描述:OCTAL BUFFERS/DRIVERS WITH 3-STATE OUTPUTS |
| 74LV540APWJ | 功能描述:74LV540APW/SOT360/TSSOP20 制造商:nexperia usa inc. 系列:* 零件状态:在售 标准包装:2,500 |
| 74LV541 | 制造商:PHILIPS 制造商全称:NXP Semiconductors 功能描述:Octal buffer/line driver 3-State |
发布紧急采购，3分钟左右您将得到回复。