|
|
PDF HV7800 Data sheet ( Hoja de datos )
| Número de pieza | HV7800 | |
| Descripción | High Side Current Monitor | |
| Fabricantes | Supertex | |
| Logotipo |  |
|
Hay una vista previa y un enlace de descarga de HV7800 (archivo pdf) en la parte inferior de esta página. Total 7 Páginas | ||
|
No Preview Available !
Supertex inc.
HV7800
High Side Current Monitor
8.0 to 450V
Voltage Gain of 1
Features
►►Supply voltages from 8V to 450V
►►Voltage output device
►►Typical gain 1±1%
►►Max VSENSE 500mV
►►Fast rise and fall time, 700ns to 2.0µs
►►Maximum quiescent current 50µA
►►5-Lead SOT-23 Package
Applications
►► SMPS current monitor
►► Battery current monitor
►► Motor controls
►► Telecom
General Description
The HV7800 high side current monitor IC transfers a high-
side current measurement voltage to its ground referenced
output with an accurate voltage gain of one. The measurement
voltage typically originates at a current sense resistor which
is located in a “high side” circuit, such as the positive supply
line.
This monitor IC features a very wide input voltage range, high
accuracy of transfer ratio, small size, low component count,
low power consumption, ease of use, and low cost. Offline,
battery and portable applications can be served equally well
due to the wide input voltage range and the low quiescent
current of the HV7800.
Typical Application Circuit
8V to 450V Input
VSENSE
ISENSE
RSENSE
RP (optional)
VOUT = VSENSE
IN LOAD
HV7800
GND
OUT
VOUT
V
R
Doc.# DSFP-HV7800
A062813
Supertex inc.
www.supertex.com
1 page  
Block Diagram
VSENSE
ISENSE
RSENSE
RP (optional)
IN LOAD
RA
HV7800
Principle of Operation
The operational amplifier and MOSFET force the voltage
across RA to track VSENSE within the limit of the offset voltage
of the opamp, i.e. VRA = VSENSE.
The current through RA returns to ground through RB. RA and
RB are integrated, exhibiting tight matching and excellent
tracking. By design, RA and RB have the same resistance.
Consequently, VRA is equal to VRB, resulting in a voltage gain
of 1.
Bias
Circuits
OUT Pin Loading Effects
Note that the OUT pin has a typical output resistance of
3.6kΩ. Loading the output causes the voltage gain to drop
and rise/fall time to increase.
RB
HV7800
GND
VOUT
OUT
For example, assuming an output resistance of 3.6kΩ, the
load resistance should exceed 3.6MΩ in order to limit the
drop in gain to 1 part in 1000.
Again assuming an output resistance of 3.6kΩ, capacitive
loading of 30pF results in a response pole with a time
constant of 100ns, not yet high enough to materially affect
the output rise and fall time (about 700ns).
Application Information
General
The HV7800 high side current monitor IC features accurate
current sensing, small size, low component count, low power
consumption, exceptional input voltage range, ease of use
and low cost.
The part typically performs the measurement of line or
load current for overcurrent protection, metering or current
regulation.
Sense Resistor Considerations
Choose a sense resistor that will not exceed 500mV during
normal operating conditions. Limit the power dissipation in
the sense resistor to whatever is practical; a high sense
voltage benefits accuracy, but increases power dissipation.
Consider the use of Kelvin connections for applications
where considerable voltage drops may occur in the PCB
traces that carry the current to be measured to the sense
resistor. A layout pattern that minimizes voltage across the
sense lines is shown below.
High side current sensing, as opposed to ground referenced
or low side current sensing, is desirable or required when:
+ VSENSE -
►► The current to be measured does not flow in a circuit
associated with ground.
►► The measurement at ground level can lead to ambiguity
due to changes in the grounding arrangement during
field use.
►► Introduction of a sense resistor in the system ground
is undesirable due to issues with safety, EMI, or signal
degradation caused by common impedance coupling.
IN LOAD
RSENSE
Choose a low inductance type sense resistor if preservation of
bandwidth is important. The use of Kelvin connections helps
by excluding the inductive voltage drop across the traces
leading to the sense resistor. The inductive voltage drop may
be substantial when operating at high frequencies.
Doc.# DSFP-HV7800
A062813
Supertex inc.
5 www.supertex.com
5 Page | ||
| Páginas | Total 7 Páginas | |
| PDF Descargar | [ Datasheet HV7800.PDF ] | |
Hoja de datos destacado
| Número de pieza | Descripción | Fabricantes |
| HV7800 | High Side Current Monitor | Supertex |
| HV7801 | High Side Current Monitor | Supertex |
| HV7802 | High Side Current Monitor | Supertex |
| Número de pieza | Descripción | Fabricantes |
| SLA6805M | High Voltage 3 phase Motor Driver IC. |
 Sanken |
| SDC1742 | 12- and 14-Bit Hybrid Synchro / Resolver-to-Digital Converters. |
 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, |
| DataSheet.es | 2020 | Privacy Policy | Contacto | Buscar |