Electronic Components Datasheet Search
  English  ▼
ALLDATASHEET.NET

X  

HT77S11 Datasheet(PDF) 7 Page - Holtek Semiconductor Inc

Part # HT77S11
Description  High Efficiency Synchronous Step-Up DC/DC Converter
Download  16 Pages
Scroll/Zoom Zoom In 100%  Zoom Out
Manufacturer  HOLTEK [Holtek Semiconductor Inc]
Direct Link  http://www.holtek.com
Logo HOLTEK - Holtek Semiconductor Inc

HT77S11 Datasheet(HTML) 7 Page - Holtek Semiconductor Inc

Back Button HT77S11 Datasheet HTML 3Page - Holtek Semiconductor Inc HT77S11 Datasheet HTML 4Page - Holtek Semiconductor Inc HT77S11 Datasheet HTML 5Page - Holtek Semiconductor Inc HT77S11 Datasheet HTML 6Page - Holtek Semiconductor Inc HT77S11 Datasheet HTML 7Page - Holtek Semiconductor Inc HT77S11 Datasheet HTML 8Page - Holtek Semiconductor Inc HT77S11 Datasheet HTML 9Page - Holtek Semiconductor Inc HT77S11 Datasheet HTML 10Page - Holtek Semiconductor Inc HT77S11 Datasheet HTML 11Page - Holtek Semiconductor Inc Next Button
Zoom Inzoom in Zoom Outzoom out
 7 / 16 page
background image
HT77S10/HT77S11
Rev. 1.10
7
March 11, 2010
Ripple Voltage vs Output Current
0
20
40
60
80
100
120
140
0
50
100
150
200
250
300
350
400
450
500
550
Output Current (mA)
HT77S10
VOUT=3.3V
L=22uH
CIN=100uF
COUT=100uF
VIN=1.2V
VIN=2.4V
Functional Description
These devices use minimum off-time, current limited
pulse-frequency modulation, PFM, techniques for out-
put voltage regulation. The PFM control circuitry acts to
control the energy stored in an external inductor to regu-
late the output voltage to the correct level. Using PFM
for control offers the advantages of very low quiescent
currents.
The device output voltage is continuously monitored us-
ing an internal comparator. The output status of the
comparator is then used to determine what action the
control logic should take to correct any differences be-
tween the actual output voltage and the required volt-
age. The variable switching frequency depends upon
the input voltage and the load demands but can have a
frequency of up to 500kHz. The maximum current of the
internal NMOS power switching transistor is fixed at 1A
for the HT77S10 and 0.55A for the HT77S11.
The switching frequency is controlled by two internal
single shot circuits that generate pulses of 0.9
ms typical
minimum off-time and 4
ms typical maximum on-time. If
the circuitry detects that the output voltage is lower than
the required voltage, the control circuitry will ensure that
more inductor energy is transferred to the load. Refer to
the block diagram to see how this regulation is imple-
mented using the following two ON and OFF steps:
· ON Step
During this step, the NMOS transistor will be switched
on which effectively connects the LX pin to ground,
and allows energy to build up in the inductor as sup-
plied by VIN. Inductor energy build up is allowed to
continue until the inductor current reaches a maxi-
mum of 1A for the HT77S10 and 0.55A for the
HT77S11 or if the on time exceeds 4
ms.
· OFF Step
The energy stored in the inductor during the ON Step
is now transferred to the load via the synchronous
switch for a minimum time of 0.9
ms. When the output
voltage is less than the required regulated voltage the
synchronous switch will switch off which will reduce
the inductor current to zero. It is during this cycle that
the PMOS power transistor is switched on which
shunts its body diode, resulting in enhanced conver-
sion efficiency.
As the design of these devices uses an internal synchro-
nous rectifier, there is no requirement to provide the
usual external Schottky diode. This gives users the ad-
vantage of smaller circuit board areas and reduced
costs.
Low Voltage Start-up
These devices can provide a very low start up voltage
down to 0.7V. When power is first applied, the synchro-
nous switch will be initially off but energy will be trans-
ferred to the load through its intrinsic body diode.
Voltage Reference
The internal voltage reference circuit supplies a nominal
voltage of 1.3V on the REF pin. Up to 150
mA can be
sourced on this pin for use by external circuits. The ref-
erence voltage provided here offers excellent load regu-
lation characteristics, however a bypass capacitor of
0.1
mF should be connected for proper operation.


Similar Part No. - HT77S11

ManufacturerPart #DatasheetDescription
logo
Holtek Semiconductor In...
HT77S11 HOLTEK-HT77S11 Datasheet
537Kb / 16P
   High Efficiency Synchronous Step-Up DC/DC Converter
More results

Similar Description - HT77S11

ManufacturerPart #DatasheetDescription
logo
Analog Intergrations Co...
AIC1620 AIC-AIC1620 Datasheet
456Kb / 12P
   High Efficiency Synchronous Step-Up DC/DC Converter
logo
Silicon Standard Corp.
SS6620 SSC-SS6620 Datasheet
640Kb / 12P
   High Efficiency Synchronous Step-Up DC/DC Converter
logo
Holtek Semiconductor In...
HT77S10 HOLTEK-HT77S10 Datasheet
537Kb / 16P
   High Efficiency Synchronous Step-Up DC/DC Converter
logo
Analog Intergrations Co...
AIC1610 AIC-AIC1610 Datasheet
651Kb / 16P
   HIGH EFFICIENCY SYNCHRONOUS STEP-UP DC/DC CONVERTER
logo
Silicon Standard Corp.
SS6610G SSC-SS6610G Datasheet
1Mb / 16P
   High-efficiency Synchronous Step-up DC/DC Converter
logo
ELM Electronics
ELM620BA ELM-ELM620BA Datasheet
892Kb / 10P
   high efficiency synchronous PWM step up DC/DC converter
logo
SHENZHEN FUMAN ELECTRON...
FM2306 FUMAN-FM2306 Datasheet
619Kb / 7P
   High efficiency PFM synchronous step-up DC/DC converter
logo
Shenzhen Huazhimei Semi...
HM6313 HMSEMI-HM6313 Datasheet
1Mb / 11P
   High Efficiency Low Voltage Synchronous Step-up DC/DC Converter
logo
Active-Semi, Inc
ACT6305 ACTIVE-SEMI-ACT6305_11 Datasheet
432Kb / 9P
   Low Input High Efficiency Synchronous Step-Up DC/DC Converter
Rev 2, 22-Feb-11
logo
AiT Semiconductor Inc.
A7544 AITSEMI-A7544 Datasheet
783Kb / 14P
   DC-DC CONVERTER BOOST (STEP-UP) HIGH EFFICIENCY 5A SYNCHRONOUS
REV1.0
More results


Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16


Datasheet Download

Go To PDF Page


Link URL




Privacy Policy
ALLDATASHEET.NET
Does ALLDATASHEET help your business so far?  [ DONATE ] 

About Alldatasheet   |   Advertisement   |   Contact us   |   Privacy Policy   |   Link Exchange   |   Manufacturer List
All Rights Reserved©Alldatasheet.com


Mirror Sites
English : Alldatasheet.com  |   English : Alldatasheet.net  |   Chinese : Alldatasheetcn.com  |   German : Alldatasheetde.com  |   Japanese : Alldatasheet.jp
Russian : Alldatasheetru.com  |   Korean : Alldatasheet.co.kr  |   Spanish : Alldatasheet.es  |   French : Alldatasheet.fr  |   Italian : Alldatasheetit.com
Portuguese : Alldatasheetpt.com  |   Polish : Alldatasheet.pl  |   Vietnamese : Alldatasheet.vn
Indian : Alldatasheet.in  |   Mexican : Alldatasheet.com.mx  |   British : Alldatasheet.co.uk  |   New Zealand : Alldatasheet.co.nz
Family Site : ic2ic.com  |   icmetro.com