- 您现在的位置：买卖IC网 > PDF目录68410 > TC7662BEOAG SWITCHED CAPACITOR REGULATOR, 35 kHz SWITCHING FREQ-MAX, PDSO8 PDF资料下载
参数资料
| 型号： | TC7662BEOAG |
| 元件分类： | 稳压器 |
| 英文描述： | SWITCHED CAPACITOR REGULATOR, 35 kHz SWITCHING FREQ-MAX, PDSO8 |
| 封装： | SOIC-8 |
| 文件页数： | 7/11页 |
| 文件大小： | 92K |
| 代理商： | TC7662BEOAG |
5
TC7662B
CHARGE PUMP DC-TO-DC
VOLTAGE CONVERTER
TC7662B-8 9/11/96
2001 Microchip Technology Inc.
DS21469A
Paralleling Devices
Any number of TC7662B voltage converters may be
paralleled to reduce output resistance (Figure 5). The reser-
voir capacitor, C2, serves all devices, while each device
requires its own pump capacitor, C1. The resultant output
resistance would be approximately:
ROUT (of TC7662B)
n (number of devices)
ROUT =
Changing the TC7662B Oscillator Frequency
It may be desirable in some applications (due to noise or
other considerations) to increase the oscillator frequency.
This is achieved by one of several methods described
below:
By connecting the BOOSTPin (Pin 1) to V+, the oscillator
charge and discharge current is increased and, hence the
oscillator frequency is increased by approximately 3-1/2
times. The result is a decrease in the output impedance and
ripple. This is of major importance for surface mount appli-
cations where capacitor size and cost are critical. Smaller
capacitors, e.g., 0.1
F, can be used in conjunction with the
Boost Pin in order to achieve similar output currents com-
pared to the device free running with C1 = C2 = 1F or 10F.
(Refer to graph of Output Source Resistance as a Function
of Oscillator Frequency).
Increasing the oscillator frequency can also be achieved
by overdriving the oscillator from an external clock as shown
in Figure 7. In order to prevent device latchup, a 1k
resistor
must be used in series with the clock output. In a situation
where the designer has generated the external clock fre-
quency using TTL logic, the addition of a 10k
pullup
resistor to V+ supply is required. Note that the pump fre-
quency with external clocking, as with internal clocking, will
be 1/2 of the clock frequency. Output transitions occur on the
positive-going edge of the clock.
Figure 6. Cascading Devices for Increased Output Voltage
1
2
3
4
8
7
6
5
V+
1
2
3
4
8
7
6
5
10
F
10
F
"n"
"1"
10
F
VOUT
*VOUT = –nV+
+
TC7662B
10
F
Cascading Devices
The TC7662B may be cascaded as shown to produce
larger negative multiplication of the initial supply voltage.
However, due to the finite efficiency of each device, the
practical limit is 10 devices for light loads. The output voltage
is defined by:
VOUT = – n(VIN)
where n is an integer representing the number of devices
cascaded. The resulting output resistance would be ap-
proximately the weighted sum of the individual TC7662B
ROUT values.
Figure 5. Paralleling Devices
1
2
3
4
8
7
6
5
TC7662B
+
V +
+
CMOS
GATE
10
F
VOUT
10
F
1 k
V +
Figure 7. External Clocking
It is also possible to increase the conversion efficiency
of the TC7662B at low load levels by lowering the oscillator
frequency. This reduces the switching losses, and is shown
in Figure 8. However, lowering the oscillator frequency will
cause an undesirable increase in the impedance of the
pump (C1) and reservoir (C2) capacitors; this is overcome by
increasing the values of C1 and C2 by the same factor that
the frequency has been reduced. For example, the addition
of a 100pF capacitor between pin 7 (Osc) and V+ will lower
the oscillator frequency to 1kHz from its nominal frequency
of 10kHz (multiple of 10), and thereby necessitate a corre-
sponding increase in the value of C1 and C2 (from 10F to
100
F).
1
2
3
4
8
7
6
5
TC7662B
V
+
1
2
3
4
8
7
6
5
TC7662B
C1
RL
C2
C1
"n"
"1"
+
相关PDF资料 |
PDF描述 |
|---|---|
| TDA16846-2G | 0.1 A POWER FACTOR CONTROLLER, 98 kHz SWITCHING FREQ-MAX, PDSO14 |
| TDA16847G | 0.1 A POWER FACTOR CONTROLLER, 98 kHz SWITCHING FREQ-MAX, PDSO14 |
| TH74KA22BVWKSGD/T | SPECIALTY ANALOG CIRCUIT, CQCC84 |
| TH74KB22B.VWKNGD/T | SPECIALTY ANALOG CIRCUIT, CQCC84 |
| TH74KA22BVWKNNG | SPECIALTY ANALOG CIRCUIT, CQCC84 |
相关代理商/技术参数 |
参数描述 |
|---|---|
| TC7662BEPA | 功能描述:电荷泵 High Voltage RoHS:否 制造商:Maxim Integrated 功能:Inverting, Step Up 输出电压:- 1.5 V to - 5.5 V, 3 V to 11 V 输出电流:100 mA 电源电流:1 mA 最大工作温度:+ 70 C 封装 / 箱体:SOIC-8 Narrow 封装:Tube |
| TC76B-1-101 | 功能描述:TRIMMER 100 OHM 0.1W TH RoHS:否 类别:电位计，可变电阻器 >> 微調器 系列:Trimpot® TC76 - 封闭框架 标准包装:500 系列:Trimpot® TC86 - 开放框架 电阻（欧姆）:100k 功率（瓦特）:0.3W 容差:±20% 温度系数:±250ppm/°C 匝数:单路 调节型:顶部调节 电阻材料:金属陶瓷 安装类型:通孔 端接类型:PC 引脚 包装:散装 尺寸/尺寸:方形 - 0.303" L x 0.268" W x 0.299" H（7.70mm x 6.80mm x 7.60mm） 其它名称:TC86P-104 |
| TC76N-1-101A | 制造商:Bourns Inc 功能描述: |
| TC76N-1-504A | 制造商:Bourns Inc 功能描述: |
| TC76P-1-102 | 制造商:Bourns Inc 功能描述: |
发布紧急采购，3分钟左右您将得到回复。