- 您现在的位置：买卖IC网 > PDF目录378619 > ILC6360CIR-ADJ (Impala Linear Corporation) STEP-UP/STEP DOWN DC-DC CONVERTER FOR 1-CELL LITHIUM-LON BATTERIES PDF资料下载
参数资料
| 型号： | ILC6360CIR-ADJ |
| 厂商： | Impala Linear Corporation |
| 元件分类： | DC/DC变换器 |
| 英文描述： | STEP-UP/STEP DOWN DC-DC CONVERTER FOR 1-CELL LITHIUM-LON BATTERIES |
| 中文描述： | STEP-UP/STEP向下的DC - DC转换器，用于1节锂离子电池 |
| 文件页数： | 6/14页 |
| 文件大小： | 687K |
| 代理商： | ILC6360CIR-ADJ |
Step-Up/Step-Down DC-DC Converter for 1-Cell Lithium-Ion Batteries
Impala Linear Corporation
6
(408) 574-3939
www.impalalinear.com
Jan 1999
ILC6360 1.1
At the start of one of the buck mode cycles, current starts to
flow in the inductor. If the input voltage is greater than the
output voltage, a normal PWM cycle will not stop the current
build up in the inductor. Current continues to build up in the
inductor and flows into the capacitor causing the capacitor
voltage to build up as t
2
. At some point the PFM limit will be
exceeded and the regulator will stop the normal PWM cycle
and turn off. The energy stored in the inductor, 1/2*LI
2
, will
be dissipated in the pass transistor. The current in the
inductor will drop to zero and the “buck” cycle will start all
over again.
This mode of operation has similar efficiency as a linear
regulator. The power dissipation and efficiency of the regu-
lator is similar to a low dropout linear regulator :
Power dissipiation, P
d
= I
OUT
(V
IN
- V
OUT
)
Efficiency,
η
= V
OUT
/V
IN
The advantage of this circuit is that there is no mode
switching required by the user, it is automatic in the opera-
tion of the circuit. For example, in the limit where V
IN
and
V
OUT
are approximately equal, a mixture of PFM and PWM
cycles will occur to maintain the output voltage in regula-
tion.
For the ILC6360 the buck mode of operation is
limited to an input voltage 800mV higher than the out-
put voltage or less.
The output ripple will increase because of the larger cur-
rent ripple associated with this mode of operation. The
peak inductor current, I
peak
, is about double the average
output current. A large output capacitor with low ESR will
decrease the output ripple voltage. A smaller inductor will
reduce the time needed to charge up the inductor to maxi-
mum current. As a result, the output voltage ripple will
decrease. A first order approximate equation for output rip-
ple is as shown below :
V
ripple
= ( K*L*I
OUT
2 ) / C
OUT
where, L is the inductor value, C
OUT
is the output capacitor
value, I
OUT
is the regulator output current and K = 2.2.
PWM Mode Operation
The ILC6360 uses a PWM or Pulse Width Modulation tech-
nique. The switches are constantly driven at typically
300kHz. The control circuitry varies the power being deliv-
ered to the load by varying the on-time, or duty cycle, of the
switch SW1 (see fig. 2). Since more on-time translates to
higher current build-up in the inductor, the maximum duty
cycle of the switch determines the maximum load current
that the device can support.
There are two key advantages of the PWM type controllers.
First, because the controller automatically varies the duty
cycle of the switch’s on-time in response to changing load
conditions, the PWM controller will always have an opti-
mized waveform for a steady-state load. This translates to
very good efficiency at high currents and minimal ripple on
the output. Ripple is caused by the constant charging and
discharging of the output capacitor.
The other key advantage of the PWM type controllers is that
the radiated noise due to the switching transients will
always occur at the (fixed) switching frequency harmonics.
Many applications do not care much about switching noise,
but certain types of applications, especially communication
equipment, need to minimize the high frequency interfer-
ence within their system as much as possible. Using a
boost converter will cause higher frequency noise to be
generated; using a PWM converter makes that noise high-
ly predictable; thus easier to filter out.
There are downsides of PWM approaches, especially at
very low currents. Because the PWM technique relies on
constant switching and varying duty cycle to match the load
conditions, there is some point where the load current gets
too small to be handled efficiently. An actual switch con-
sumes some finite amount of current to switch on and off; at
very low currents this can be of the same magnitude as the
load current itself, driving switching efficiencies down to
50% and below.
PFM Mode Operation
The ILC6360 overcomes this limitation by automatically
switching over to a PFM, or Pulse Frequency Modulation,
technique at low currents. This technique conserves power
loss by only switching the output if the current drain
requires it. As shown in figure 3, the waveform actually
skips pulses depending on the power needed by the out-
put. This technique is also called “pulse skipping” because
of this characteristic.
V
SET
V
OUT
Switch Waveform
Fig 3: PFM Waveform
相关PDF资料 |
PDF描述 |
|---|---|
| ILC6360 | STEP-UP/STEP DOWN DC-DC CONVERTER FOR 1-CELL LITHIUM-LON BATTERIES |
| ILC6363CIR50X | Step-Up DC-DC Converter for One-Cell Lithium-Ion Batteries |
| ILC6363CIRADJX | Step-Up DC-DC Converter for One-Cell Lithium-Ion Batteries |
| ILC6363 | Step-Up DC-DC Converter for One-Cell Lithium-Ion Batteries |
| ILC6375 | 1 AMP SOT - 89 STEP DOWN PWM SWITCHER CONTROLLER |
相关代理商/技术参数 |
参数描述 |
|---|---|
| ILC6363 | 制造商:FAIRCHILD 制造商全称:Fairchild Semiconductor 功能描述:Step-Up DC-DC Converter for One-Cell Lithium-Ion Batteries |
| ILC6363CIR33X | 功能描述:开关变换器、稳压器与控制器 DC/DC RoHS:否 制造商:Texas Instruments 输出电压:1.2 V to 10 V 输出电流:300 mA 输出功率: 输入电压:3 V to 17 V 开关频率:1 MHz 工作温度范围: 安装风格:SMD/SMT 封装 / 箱体:WSON-8 封装:Reel |
| ILC6363CIR50X | 功能描述:直流/直流开关调节器 Step-Up/Step Down DC-DC RoHS:否 制造商:International Rectifier 最大输入电压:21 V 开关频率:1.5 MHz 输出电压:0.5 V to 0.86 V 输出电流:4 A 输出端数量: 最大工作温度: 安装风格:SMD/SMT 封装 / 箱体:PQFN 4 x 5 |
| ILC6363CIR50X_Q | 功能描述:DC/DC 开关控制器 Step-Up/Step Down DC-DC RoHS:否 制造商:Texas Instruments 输入电压:6 V to 100 V 开关频率: 输出电压:1.215 V to 80 V 输出电流:3.5 A 输出端数量:1 最大工作温度:+ 125 C 安装风格: 封装 / 箱体:CPAK |
| ILC6363CIRADJX | 功能描述:开关变换器、稳压器与控制器 DC/DC RoHS:否 制造商:Texas Instruments 输出电压:1.2 V to 10 V 输出电流:300 mA 输出功率: 输入电压:3 V to 17 V 开关频率:1 MHz 工作温度范围: 安装风格:SMD/SMT 封装 / 箱体:WSON-8 封装:Reel |
发布紧急采购，3分钟左右您将得到回复。