DataSheet.es    


PDF DS1227 Data sheet ( Hoja de datos )

Número de pieza DS1227
Descripción KickStarter Chip
Fabricantes Dallas Semiconducotr 
Logotipo Dallas Semiconducotr Logotipo



Hay una vista previa y un enlace de descarga de DS1227 (archivo pdf) en la parte inferior de esta página.


Total 20 Páginas

No Preview Available ! DS1227 Hoja de datos, Descripción, Manual

www.DataSheet4U.com
DS1227
DS1227
KickStarter Chip
FEATURES
Provides step-up regulation and microenergy
management for battery-operated systems
Converts +3V to +6V DC input power source to +5V
DC out for system power
“Kickstarts” system power upon detection of external
stimuli:
- Clock/calendar alarm
- Sensor trip; such as from a photo diode
- Incoming activity to a serial port
- Any low-level signal transition
Shuts down microcontroller power under software
control when operation complete
Provides 3 auxiliary power outputs for independent
powering of system functions
Allows design of “power on demand” systems
Insures maximum life of main power source
Ideally suited for DS5000-based systems
Available in 20-pin DIP or SOIC packages
Operating temperature range of –40°C to +85°C
PIN ASSIGNMENT
VCCO2
VCCO3
VCCO1
1
2
3
20 VCCO4
19 MODE4
18 SENSE
PWRON 4
17 INT/ACK
VDCO
VDCI
5
6
16 OSCEXT
15 BOOST
GND 7
14 ON1
ON/OFF3 8
13 ON4
OFF1 9
12 RXIN
ON2/OFF2 10
11 RXOUT
20-Pin DIP (300 Mil)
See Mech. Drawing - Sect. 16, Pg. 1
VCCO2
VCCO3
1 20 VCCO4
2 19 MODE4
VCCO1
3 18 SENSE
PWRON
4 17 INT/ACK
VDCO 5 16 OSCEXT
VDCI
6 15 BOOST
GND 7 14 ON1
ON/OFF3
8 13 ON4
OFF1
9 12 RXIN
ON2/OFF2 10 11 RXOUT
20-Pin SOIC (300 Mil)
See Mech. Drawing - Sect. 16, Pg. 6
ORDERING INFORMATION
DS1227:
20-Pin DIP
DS1227S: 20-Pin SOIC
DESCRIPTION
The DS1227 Kickstarter is a unique CMOS circuit which
combines power conversion and microenergy manage-
ment functions for battery operated systems. Using its
integral DC-DC converter, the DS1227 supplies +5V on
demand from either a 3– or 6–volt battery input. The pri-
mary +5V output, typically tied to the microcontroller’s
VCC pin, is “kickstarted” on in response to any one of
several possible momentary, external signal transitions.
Two auxiliary +5V power supply outputs can then be in-
dependently enabled or disabled under software con-
trol. When the primary power supply output is disabled,
also under software control, the auxiliary power supply
outputs remain in the state selected. In this manner, in-
dividual portions of the system can be powered only
022698 1/20

1 page




DS1227 pdf
DS1227
Initially, when VCCO1 is off, the INT/ACK pin is collapsed
to ground. At the time that voltage is switched to the
VCCO1 output pin during kickstarting, the INT/ACK pin
will be latched such that it will remain in a low state. This
signals the microcontroller that a power on reset has oc-
curred. The OFF1, ON2/OFF2, and ON3/OFF3 inputs
are all ignored until the microcontroller acknowledges
this power on reset condition. This acknowledgement is
performed via the same INT/ACK pin, which also per-
forms the function of an interrupt acknowledge input.
This is made possible due to the fact that the pin has a
weak NMOS pulldown which forms a latch. When INT/
ACK is externally driven with a sufficiently strong high
signal (as described in the “Electrical Characteristics”
section) the state of the latch will be switched and as a
result the interrupt condition will be reset.
After the power on reset interrupt has been acknowl-
edged and the DS1227 is in a power on condition, the
INT/ACK pin will be again taken low to signal the detec-
tion of active signalling on the ON1 or SENSE inputs.
Further activity on the RXIN input will not cause a sub-
sequent interrupt condition. The INT/ACK can be re-
turned to its high (reset) state again by externally driving
it with a sufficiently strong high signal.
The OFF1 input is used to turn off the VCCO1 output un-
der software control. It is typically interfaced to the sys-
tem microcontroller via a port pin configured as an out-
put. As noted above, it is active only when VCCO1 is on
and INT/ACK has been set high.
STIMULUS INPUTS
ON1 is a simple TTL-level compatible input which is de-
signed to detect a negative-going edge. VCCO1 is kick-
started whenever an active edge is detected on this pin.
The RXIN input can be used to initiate the kickstarting
action in response to the detection of incoming serial
data. In this configuration, the RXIN pin is interfaced to
an incoming serial data line, typically from an RS232
transceiver. RXOUT is the corresponding output and is
used to route the serial data to the microcontroller. RXIN
remains internally disconnected from RXOUT until
VCCO1 is powered on. At that time, the two lines are con-
nected and serial data is passed straight through the de-
vice to the microcontroller.
The SENSE pin is intended to be connected to an exter-
nal sensor circuit which is powered from VCCO4. This
circuit is then momentarily powered from the Kickstart-
er’s VCCO4 output in response to a negative going edge
applied to the ON4 input. VCCO4 will stay powered for an
amount of time determined by the circuitry on the
MODE4 pin. During the time that VCCO4 is on, the
SENSE pin has an internal pulldown device which is ac-
tivated. SENSE is sampled just prior to the VCCO4 out-
put being disconnected. If SENSE is externally driven
high (VIH) at this time, it kickstarts VCCO1 power. Any
time that VCCO4 power is off, the SENSE pin appears as
a high impedance to external circuitry.
The amount of time that VCCO4 is on is determined by
the configuration of the MODE4 pin. MODE4 is intended
to either be tied high (typically to VDCO) or tied to an ex-
ternal capacitor. The VCCO4 on time is thereby deter-
mined either by the amount of time between falling
edges on ON4 or by the value of the capacitor.
If the MODE4 pin is tied high at the time that ON4 is acti-
vated, then VCCO4 will remain on until the next falling
edge is detected on ON4. Figure 5 illustrates the timing
associated with this mode of operation. If the Kickstarter
is also configured for boost regulation and VCCO1,
VCCO2, and VCCO3 are turned off, the DC-DC converter
will be briefly enabled so that +5V will be supplied on
VCCO4 for the duration of the time that it is on.
The alternative MODE4 configuration is illustrated in
Figure 6A. As shown in the figure, it is recommended for
most applications that a large resistor also be con-
nected between MODE4 and ground in addition to the
capacitor. For the configuration shown, the MODE4 pin
will be sensed low by the Kickstarter just following the
negative-going edge at ON4. Following this condition, a
constant current specified as IM4ON is supplied out of
the MODE4 pin. This will cause the voltage on MODE4
to rise linearly. VCCO4 will remain on until the voltage on
MODE4 reaches a threshold specified as VM4OFF (ap-
proximately 0.5 VDCO). At this time, VCCO4 will be shut
off. At the same time, the constant current source on the
MODE4 pin will be disconnected and an internal resis-
tive element (specified as RM4DIS) will be connected be-
tween the MODE4 pin and ground. This internal resis-
tive element along with any external resistance will
cause the voltage on the capacitor to decay exponen-
tially until it reaches a threshold specified as VM4DIS (ap-
proximately 0.1 VDCO). When this condition is reached,
the internal resistive element will be disconnected, and
the MODE4 pin will appear as a high impedance until the
next active transition occurs on ON4. The external re-
022698 5/20

5 Page





DS1227 arduino
AUXILIARY BOOST SUPPLY CONFIGURATION Figure 8
100 µH (typ.) 1N5418
VCCOAUX
270 µH (typ.)
+
+3V
200 µF (typ.)
DS1227
KICKSTARTER
OSCEXT
VDCI
VDCO
VCC01
VCC02
VCC03
BOOST
GND
DS1227
The DC-DC converter’s output current is provided both
by the inductor and directly from the battery. If the load
draws less than the maximum current, the VDCI n-chan-
nel MOSFET is turned on only often enough to keep the
output voltage at the desired level.
If the selected inductor has too high a value, the DS1227
will not be able to deliver the desired output power, even
with the MOSFET turned on for every oscillator cycle.
The available output power can be increased by either
raising the input voltage or lowering the inductance.
This causes the current to rise at a faster rate, and re-
sults in a higher peak current at the end of each cycle.
The available output power increases since it is propor-
tional to the square of the peak inductor current. The
maximum inductance therefore is:
LMAX
+
VIN 2
8 fO PL
since :
PL
+
L
IPK2
2
fO
and :
IPK
+
VIN
2
fO L
The required output power must include what is dissi-
pated in the forward drop of the catch diode and each of
the VCCO1, VCCO2, and VCCO3 pass transistors. This
can be expressed as follows:
POUT = VF IOUT + (IOUT12 RON1 + IOUT22 RON2 +
IOUT32 RON3 + IOUT42 RON4) + VOUT IOUT
where:
IOUT
= IOUT1 + IOUT2 + IOUT3 + IOUT4
If the inductance value is too low, the current at VDCI
may rise above the maximum rating. The minimum al-
lowed inductor value is expressed by:
LMIN
+
2
VIN
fO IMAX
(IMAX ) 450 mA)
TYPES OF INDUCTORS
The following is a brief discussion of various types of in-
ductors which may be typically used with the DS1227
Kickstarter to facilitate boost mode operation. Table 1
lists some typical manufacturers of these types of induc-
tors. Table 2 summarizes performance of the circuit for
various inductors.
Molded Inductors
These are cylindrically wound coils which look similar to
1-watt resistors. They have the advantages of low cost
and ease of handling, but have higher resistance, higher
losses, and lower power handling capability than other
types of inductors.
Potted Toroidal Inductors
A typical 1 mH, 0.82 ohm potted toroidal inductor (Dale
TE-3Q4TA) is 0.685 in diameter by 0.385 high and
022698 11/20

11 Page







PáginasTotal 20 Páginas
PDF Descargar[ Datasheet DS1227.PDF ]




Hoja de datos destacado

Número de piezaDescripciónFabricantes
DS122016k Nonvolatile SRAMDallas
Dallas
DS1220Y16k Nonvolatile SRAMDallas
Dallas
DS1221Nonvolatile Controller x 4 ChipDallas
Dallas
DS1222BankSwitch ChipDallas
Dallas

Número de piezaDescripciónFabricantes
SLA6805M

High Voltage 3 phase Motor Driver IC.

Sanken
Sanken
SDC1742

12- and 14-Bit Hybrid Synchro / Resolver-to-Digital Converters.

Analog Devices
Analog Devices


DataSheet.es es una pagina web que funciona como un repositorio de manuales o hoja de datos de muchos de los productos más populares,
permitiéndote verlos en linea o descargarlos en PDF.


DataSheet.es    |   2020   |  Privacy Policy  |  Contacto  |  Buscar