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參數(shù)資料
| 型號： | TC7660SCPA |
| 廠商： | Microchip Technology Inc. |
| 英文描述： | SUPER CHARGE PUMP DC-TO-DC VOLTAGE CONVERTER |
| 中文描述： | 超級電荷泵型DC - DC電壓轉(zhuǎn)換器 |
| 文件頁數(shù)： | 7/9頁 |
| 文件大小： | 131K |
| 代理商： | TC7660SCPA |
4-57
TELCOM SEMICONDUCTOR, INC.
7
6
5
4
3
1
2
8
TC7660
CHARGE PUMP DC-TO-DC
VOLTAGE CONVERTER
Figure 5. Increased Output Voltage by Cascading Devices
Figure 4. Paralleling Devices Lowers Output Impedance
device latch-up, a 1k
resistor must be used in series with
the clock output. In a situation where the designer has
generated the external clock frequency using TTL logic, the
addition of a 10k
pull-up resistor to V
+
supply is required.
Note that the pump frequency 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.
It is also possible to increase the conversion efficiency
of the TC7660 at low load levels by lowering the oscillator
frequency. This reduces the switching losses, and is achieved
OSC
, as shown in
Figure 7. Lowering the oscillator frequency will cause an
undesirable increase in the impedance of the pump (C
1
) and
the reservoir (C
2
) capacitors. To overcome this, increase the
values of C
1
and C
2
by the same factor that the frequency
has been reduced. For example, the addition of a 100pF
capacitor between pin 7 (OSC) and pin 8 (V
+
) will lower the
oscillator frequency to 1kHz from its nominal frequency of
10kHz (a multiple of 10), and necessitate a corresponding
increase in the values of C
1
and C
2
(from 10
μ
F to 100
μ
F).
Cascading Devices
The TC7660 may be cascaded as shown (Figure 6) 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:
V
OUT
= –n (V
IN
)
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 TC7660
R
OUT
values.
Changing the TC7660 Oscillator Frequency
It may be desirable in some applications (due to noise or
other considerations) to increase the oscillator frequency.
This is achieved by overdriving the oscillator from an exter-
nal clock, as shown in Figure 6. In order to prevent possible
1
2
3
4
8
7
6
5
TC7660
V+
1
2
3
4
8
7
6
5
TC7660
C1
RL
C2
C1
"n"
"1"
+
1
2
3
4
8
7
6
5
V+
1
2
3
4
8
7
6
5
10
μ
F
10
μ
F
"n"
"1"
10
μ
F
VOUT
1. VOUT= –n V+for 1.5V V 10V
NOTES:
*
*
≤
≤
+
+
+
TC7660
TC7660
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| TC7660SEOA | SUPER CHARGE PUMP DC-TO-DC VOLTAGE CONVERTER |
| TC7660SEPA | SUPER CHARGE PUMP DC-TO-DC VOLTAGE CONVERTER |
| TC7660SMJA | SUPER CHARGE PUMP DC-TO-DC VOLTAGE CONVERTER |
| TC7660HEOA | HIGH FREQUENCY 7660 DC-TO-DC VOLTAGE CONVERTER |
| TC7660HEPA | HIGH FREQUENCY 7660 DC-TO-DC VOLTAGE CONVERTER |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| TC7660SEJA | 功能描述:電荷泵 High Voltage RoHS:否 制造商:Maxim Integrated 功能:Inverting, Step Up 輸出電壓:- 1.5 V to - 5.5 V, 3 V to 11 V 輸出電流:100 mA 電源電流:1 mA 最大工作溫度:+ 70 C 封裝 / 箱體:SOIC-8 Narrow 封裝:Tube |
| TC7660SEOA | 功能描述:電荷泵 High Voltage RoHS:否 制造商:Maxim Integrated 功能:Inverting, Step Up 輸出電壓:- 1.5 V to - 5.5 V, 3 V to 11 V 輸出電流:100 mA 電源電流:1 mA 最大工作溫度:+ 70 C 封裝 / 箱體:SOIC-8 Narrow 封裝:Tube |
| TC7660SEOA | 制造商:Microchip Technology Inc 功能描述:DC/DC Charge Pump Converter (DC-DC) IC |
| TC7660SEOA713 | 功能描述:電荷泵 High Voltage RoHS:否 制造商:Maxim Integrated 功能:Inverting, Step Up 輸出電壓:- 1.5 V to - 5.5 V, 3 V to 11 V 輸出電流:100 mA 電源電流:1 mA 最大工作溫度:+ 70 C 封裝 / 箱體:SOIC-8 Narrow 封裝:Tube |
| TC7660SEPA | 功能描述:電荷泵 High Voltage RoHS:否 制造商:Maxim Integrated 功能:Inverting, Step Up 輸出電壓:- 1.5 V to - 5.5 V, 3 V to 11 V 輸出電流:100 mA 電源電流:1 mA 最大工作溫度:+ 70 C 封裝 / 箱體:SOIC-8 Narrow 封裝:Tube |
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