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参数资料
| 型号： | NCV8855BMNR2G |
| 厂商： | ON Semiconductor |
| 文件页数： | 16/24页 |
| 文件大小： | 0K |
| 描述： | IC REG QD BUCK/LINEAR 40QFN |
| 标准包装： | 1 |
| 拓扑： | 降压（降压）（2），线性（LDO）（2） |
| 功能： | 汽车无线电设备和仪表板电源 |
| 输出数： | 4 |
| 频率 - 开关： | 170kHz |
| 电压/电流 - 输出 1： | 控制器 |
| 电压/电流 - 输出 2： | 可调式，2.5A |
| 电压/电流 - 输出 3： | 控制器 |
| 带 LED 驱动器： | 无 |
| 带监控器： | 无 |
| 带序列发生器： | 是 |
| 电源电压： | 9 V ~ 18 V |
| 工作温度： | -40°C ~ 105°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 40-VFQFN 裸露焊盘 |
| 供应商设备封装： | 40-QFN（6x6） |
| 包装： | 标准包装 |
| 其它名称： | NCV8855BMNR2GOSDKR |
NCV8855
shutdown behavior when VOUT3 is derived from VOUT1
(as shown in Figure 1).
Startup and Shutdown Behavior
18.5 V
17.9 V
re ? start the high ? side switch in the case of a T MON_HSS TSD
event.
If thermal monitor 2 (T MON_SW ) exceeds it TSD point, the
entire chip (regardless of the state of T MON_HSS ) will latch
off, and a SYS_EN toggle will be required to restart.
VIN
SYS_EN
8V_IC
5V_IC
VOUT1
VOUT2
LDO_EN
VOUT3
VOUT4
>2.2 V
<0.8 V
4.35 V
4.2 V
4.35 V
4.2 V
>2.2 V
<0.8 V
Overcurrent Protection (SMPS1)
Overcurrent protection for SMPS1 is implemented via
V DS(on) sensing of the upper MOSFET. At the beginning of
each switching cycle, after a short blanking time, the voltage
is sampled across the upper MOSFET and compared to the
threshold set by R OCSET .
OCSET
27
Natural Startup
Natural Decay
Controlled Soft ? Star
External upper
MOSFET
ROCSET
Figure 19.
ILIMIT
In addition to the enable pins, the IC features an automatic
shutdown during a high battery condition. When VIN
exceeds 18.5 V (typ) the IC will shutdown all outputs. When
23
SN1
50 A
I LIMIT +
I pk ? pk
I LIMIT w IOUT1 MAX )
V IN falls below 17.9 V (typ), the IC will go through a typical
start up and resume normal operation.
Out ? of ? Phase Synchronization
By default, the turn ? on of SMPS2 is delayed by half the
switching cycle, which corresponds to 180 ° phase delay.
Advantages of out ? of ? phase synchronization are many.
Interleaving the current pulses at the input reduces the input
RMS current. This reduction minimizes the input filter
requirement, allowing the use of smaller components, hence
a more cost effective solution. In addition, since peak current
is reduced, emitted EMI is also reduced.
Synchronizing (SYNC)
Synchronizing the NCV8855 to an external frequency is
achieved by providing a 10 to 90% duty cycle clock to the
SNYC pin. The rising edge of the clock signal will
immediately reset the internal RAMP of SMPS2 and begin
a new pulse for SMPS2. Conversely, the falling edge of the
clock signal will immediately reset the internal RAMP of
SMPS1 and begin a new pulse for SMPS1. The first rising
edge of the external clock signal may cause a momentary
phase diversion between SMPS1 and SMPS2, but will lock
into desired phase on the subsequent falling edge. During
start up, the SYNC pin must not be held at a logic high.
Thermal Warning (HOT_FLG) and Thermal Shutdown
There are two thermal sensors in the NCV8855 devices.
If any of these two exceeds the warning threshold, the
HOT_FLG will assert low. In addition, if thermal monitor 1
(T MON_HSS ) exceeds the warning threshold, the high ? side
switch current limit will fold back to 1.4 A (typ). If
T MON_HSS exceeds its TSD point, the high ? side switch will
latch off while the other device functions will continue to
Figure 20.
If this comparator is tripped, then the pulse is immediately
halted. This operation repeats every cycle until the
overcurrent condition is removed.
The over ? current limit can be calculated with the
following equation:
R OCSET I OCSET
(eq. 1)
R DS(on)
where, I OCSET is 50 m A (typ.). To calculate the R OCSET
value, the maximum R DS(on) (at temperature) and the
minimum value of I OCSET must be used. In addition to this,
the following relationship should be met:
(eq. 2)
2
where IOUT1 (MAX) is the maximum dc current allowed,
and I pk ? pk /2 is the peak ripple current above the dc value.
This will insure that undesirable trigger of the over ? current
protection is avoided.
To protect in the case of a short circuit event, a comparator
monitoring the feedback voltage is incorporated. If the
output voltage goes below 70% of nominal after start ? up,
the part is latched off, requiring SYS_EN to be toggled to
restart the part.
The over current protection circuitry is active upon startup
(short circuit protection is not). During soft ? start, under
normal conditions, the current limit circuit should not trip.
However, with large output capacitance, the current limit
circuit may determine the output voltage rise time instead of
the soft ? start circuit. To ensure that the output voltage is
operate. A HS_EN or SYS_EN toggle will be required to
http://onsemi.com
16
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相关代理商/技术参数 |
参数描述 |
|---|---|
| NCV8855BMNR2GEVB | 功能描述:电源管理IC开发工具 SMPS ASIC RoHS:否 制造商:Maxim Integrated 产品:Evaluation Kits 类型:Battery Management 工具用于评估:MAX17710GB 输入电压: 输出电压:1.8 V |
| NCV8870 | 制造商:ONSEMI 制造商全称:ON Semiconductor 功能描述:Automotive Grade Non-Synchronous Boost Controller |
| NCV887000 | 制造商:ONSEMI 制造商全称:ON Semiconductor 功能描述:Automotive Grade Non-Synchronous Boost Controller |
| NCV887000D1R2G | 功能描述:低压差稳压器 - LDO Auto Grade Non-Sync Boost Controller RoHS:否 制造商:Texas Instruments 最大输入电压:36 V 输出电压:1.4 V to 20.5 V 回动电压（最大值）:307 mV 输出电流:1 A 负载调节:0.3 % 输出端数量: 输出类型:Fixed 最大工作温度:+ 125 C 安装风格:SMD/SMT 封装 / 箱体:VQFN-20 |
| NCV887001 | 制造商:ONSEMI 制造商全称:ON Semiconductor 功能描述:Automotive Grade Non-Synchronous Boost Controller |
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