BOM-DAT/Resistor-Dat/sample-resistor-dat/sample-resistor-dat.md
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@@ -34,6 +34,6 @@ R0003 = 0.3 mR
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## ref
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-- [[resistor-dat]] - [[sample-resistor]] - [[resistor]]
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+- [[resistor-dat]] - [[resistor-sample]] - [[resistor]]
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-
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Board-dat/OPM/OPM1181-dat/OPM1181-dat.md
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@@ -11,6 +11,11 @@ read more information at chip page [[CN3768-dat]]
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Notice if you run high charging current, add heat sink on backside would be good.
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+- fully charged voltage at around 13.55V
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+- over-charged voltage at around 14.8V
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+
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+Please note it may take a long time to fully charge a battery.
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+
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## Dimension
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![](2023-10-25-14-57-35.png)
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- [[Lead-Acid-Battery-dat]]
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-- [[OPM1181]]
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+- [[OPM1181]] - [[CN3768]]
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Chip-cn-dat/CONSONANCE-dat/CN3768-dat/CN3768-dat.md
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@@ -1,63 +1,85 @@
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+# CN3768
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-# CN3768-dat
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+- [DSE-CN3768.pdf]
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-- [[DSE-CN3768.pdf]]
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+## Overview
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-VFLOAT BAT pin , Float Charge mode 13.35 13.55 13.75 V
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+The CN3768 is a complete switching charger controller designed for 12V lead-acid batteries. It provides automatic multi-stage charging with protections and status indication. Typical applications include battery chargers and power backup systems.
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+![](2025-04-21-20-46-06.png)
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-## Features
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-- Wide Input Voltage: 6.6V to 30V
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-- Complete Charger Controller for 12V Lead-Acid Battery
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-- Charge Current Up to 4A
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-- High PWM Switching Frequency: 315KHz
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-- Fixed Over-Charge Voltage
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-- Charging Current is programmed with a sense resistor
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-- Automatic Conditioning of Deeply Discharged Batteries
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-- Automatic Recharge
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-- Charger Status Indication
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-- Soft Start
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-- Battery Overvoltage Protection
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-- Operating Ambient Temperature －40°C to ＋85°C
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-- Available in 8 Pin SOP Package
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-- Pb-free , RoHS Compliant, and Halogen Free
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+## Key Features
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+- Wide input voltage range: 6.6 V to 30 V
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+- Charge current up to 4 A
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+- High PWM switching frequency: 315 kHz
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+- Fixed over-charge voltage and automatic float charging
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+- Deep-discharge recovery (automatic trickle charge)
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+- Charge current programmed via a sense resistor
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+- Automatic recharge when battery voltage drops
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+- Sleep mode when input voltage is below battery voltage
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+- Charger status indication (open-drain CHRG output)
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+- Soft-start and battery overvoltage protection
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+- Operating ambient temperature: -40°C to +85°C
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+- Available in 8-pin SOP package
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+- Pb-free, RoHS compliant, halogen free
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-## info
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-The CN3768 charging system incorporates several automatic features to optimize battery health and longevity.
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+## Typical Applications
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-**Deeply discharged batteries** are initially trickle charged at 17.5% of the programmed constant charge current. This continues until the cell voltage reaches 75% of the regulation voltage in over-charge mode.
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+![](2025-04-21-20-50-20.png)
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-The **over-charge phase** ends when the charging current decreases to 38% of the constant charge current, at which point the system transitions to float charge mode.
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-If the battery voltage subsequently drops below 83.95% of the over-charge voltage while in float-charge mode, a **new charge cycle** automatically begins.
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+## Electrical Characteristics (summary)
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-Furthermore, the CN3768 automatically enters **sleep mode** when the input voltage falls below the battery voltage, conserving power.
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+| Parameter | Value | Notes |
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+| ------------------------------ | ----------------------------: | --------------------------------------------------------------- |
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+| Input Voltage Range | 6.6 V — 30 V | Operating VCC range |
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+| Maximum Charge Current | Up to 4 A | Limited by external components and thermal design |
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+| PWM Switching Frequency | 315 kHz | Typical internal switching frequency |
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+| Float (VFLOAT) | 13.35 V / 13.55 V / 13.75 V | Min / Typ / Max for 12 V lead-acid float charge |
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+| Deep-Discharge Trickle Current | 17.5% of Iprog | Applies until battery reaches 75% of regulation voltage |
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+| End of Over-Charge → Float | When Ichg ≤ 38% of Iprog | Transition condition to float mode |
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+| Auto-Recharge Threshold | 83.95% of over-charge voltage | If battery falls below this in float, a new charge cycle starts |
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+| Sleep Mode | Enters when VIN < BAT | Conserves power when input is lower than battery |
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+| Operating Temperature | -40°C to +85°C | Ambient temperature range |
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+| Package | 8-pin SOP | Surface-mount package |
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-![](2025-04-21-20-46-06.png)
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-## typical APPs
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-
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-![](2025-04-21-20-50-20.png)
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+## Charging Behavior (summary)
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-## Status Indication
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+- Deeply discharged batteries: initial trickle charge at ~17.5% of the programmed constant current until battery voltage reaches ~75% of the regulation (over-charge) voltage.
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+- Constant-current / over-charge: the controller charges at the programmed current until the battery voltage reaches the regulation point; over-charge phase ends when charging current falls to ~38% of the programmed current, then the controller switches to float mode.
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+- Float mode: a reduced float voltage is maintained. If battery voltage drops below ~83.95% of the over-charge voltage while in float, the CN3768 automatically starts a new charge cycle.
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+- Sleep: when input (VIN/VCC) falls below the battery voltage, the device automatically enters sleep mode to save power.
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-The CN3768 has one open-drain status outputs: CHRG. CHRG is pulled low when the charger is in trickle charge mode, constant current mode and over charge mode.
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-In float mode, CHRG becomes high impedance.
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+## Status Indication (CHRG pin)
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-When the battery is not present, the charger charges the output capacitor to the float-charge voltage.
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+The CN3768 provides a single open-drain status output, CHRG. Typically a red LED is connected between VIN (or a suitable supply) and CHRG (with a current-limiting resistor).
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-The CHRG pin should be tied to ground if charge status indication is not needed.
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+| CHRG Output | LED State (red) | Charger Status |
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+| ------------------: | --------------- | -------------------------------------------------------------- |
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+| Low (pulled to GND) | ON | Trickle charge, Constant-current charge, Over-charge |
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+| High-impedance | OFF | Float mode OR VIN below UVLO OR VIN < BAT (no battery present) |
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-The table 1 lists the indicator status and its corresponding charging status. It is supposed that red LED is
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-connected to CHRG pin.
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+Notes:
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+- If status indication is not required, tie CHRG to ground.
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+- When no battery is connected, the charger will charge the output capacitor to the float voltage and CHRG remains high-impedance.
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![](2025-04-21-20-49-33.png)
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-## ref
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-[[DSE-CN3768.pdf]]
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+## Design Notes
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+- Program charging current using the recommended sense resistor per the datasheet (Iprog determined by sense voltage / Rsense).
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+- Ensure thermal layout and component selection (inductor, diode, MOSFET) match the target current and power dissipation.
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+- Follow the datasheet for recommended input/output capacitors and compensation parts to ensure stable operation.
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+
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+
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+## References
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+
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+- [DSE-CN3768.pdf] — CN3768 datasheet / application notes
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+