Description ZXCT1010 is a high voltage side current detection monitor. Using this device eliminates the need to disturb the ground plane when inducing load currents.
It is an enhanced version of the ZXCT1009, offering reduced typical output offset and improved accuracy at low inductance voltages.
Wide input voltage 20V , as low as 2.5V, suitable for a variety of applications. The minimum operating current is only 4 microamps, and its SOT23-5 package is suitable for portable battery devices.
Features Low-Cost, Accurate High-Side Current Sense Output Voltage Scaling Up to 2.5V Sensing Voltage 2.5V–20V Supply Range 300 ns Typical Offset Current 3.5 μA Quiescent Current 1% Typical Accuracy SOT23-5 Package Applications Battery Charger Smart Battery Group DC Motor Control Over Current Monitor Power Management Programmable Current Source Enhanced High Side Current Monitor Application Circuit

Absolute Maximum Voltage Rating on Any Pin -0.6V to 20V (relative to GND) Continuous Output Current, Output, 25MA Continuous Induced Voltage, Vsense2, -0.5V to +5V Operating Temperature, Ta, -40 to 85°C Storage Temperature -55 to 150 °C module power consumption (Ta=25 °C) SOT23-5 300MW
Operation above the Absolute Maximum Ratings may cause device failure. Exposure to absolute maximum ratings for extended periods of time may degrade device reliability.
Electrical characteristics test conditions Ta=25°C, Vin=5 V, Rout=100Ω.

The maximum allowable power dissipation (pmax) of the power dissipation device in normal operation is a function of the package junction-to-ambient thermal resistance (θja), the maximum junction temperature (tjmax), and the ambient temperature (tamb), and is expressed as:
The device power consumption pd is given by the following expression:
Pd = output (VIN VOUT) watts

The following lines describe how the load current is scaled to the output voltage.
Vsense=VIN-V load
A current should be maintained at 100mV output voltage:
1) Select the value of rsense and give 50mV>vsense>500mV at full load.
For example, at 1.0A.rsense=0.1/1.0=>0.1 ohm, vsense=100mV.
2) When Vsense=100mV, select rout to give vout=100mV.
Give rearrangement 1 for Rout: Rout=Vout/(Vsense x 0.01)
rout=0.1/(0.1 x 0.01)=100Ω
Typical circuit application

If rload represents any load, including DC motors, rechargeable batteries, or other circuits that need to be monitored, rsense can be selected based on specific requirements for accuracy, size, and power rating.

Application Information (continued)

Li-Ion Charger Circuit The picture above shows the Benchmarq BQ2954 charge management IC supporting the ZXCT1010. Most of the supporting components of the BQ2954 are omitted for clarity. The design also uses the Zetex FZT789A high current super PNP as the switching transistor of the DC-DC buck converter and the fmt451 as the driving NPN for the FZT789A. The circuit can be configured to charge up to four Li-Ion batteries at a charge current of 1.25A. Charging can be terminated at maximum voltage, optional minimum current, or maximum time. come out. The switching frequency of the PWM loop is about 120kHz.

Bidirectional Current Sensing ZXCT1010 can be used to measure current bidirectionally, if two devices are connected as shown below.
If the voltage v1 is positive with respect to the voltage v2, the low power device emits light, providing a proportional output current to rout. Due to the voltage polarity across RSENSE, the upper device will be inactive and will not contribute to the output current. When NV2 is more recoverable than V1, current will flow in the opposite direction, causing the upper device to be active.
Due to the contribution of the compensation current, nonlinearity can be evident at very small values of Vsense. If the current direction is to be independently monitored, the device can use a separate output resistor. Two-way transfer function

The traced shunt resistor diagram for the low-cost solution shows the output characteristics of the device, and then the GACBR is used to perform the necessary traces for the low-cost solution to replace the traditional shunt resistor. The graph shows the linear voltage rise across the resistor due to the temperature of the material, illustrating how the rise in resistance value compensates for the overheating of the device.
The figure shows the SAP layout recommendations. The resistive part is 25mm x 0.25mm and is about 150 megohms using 1oz copper.