feature

5.4V to 24V input voltage range Five adjustable outputs: 5V@5A (PWM) 3.3V@5A (PWM) 5V@50MA always on (linear) 3.3V@50MA always on (linear) 12V/can Regulated @ 120mA Boost (PWM) > 96% Efficiency Light Load Hysteresis Mode Normal Load PWM Mode Main Regulator Switching Out of Phase 300kHz Fixed Frequency Switching rds (On) Current Sensing Over Current Reduction Bill of Materials ;Maximum Efficiency Optional Current Sensing Resistor for Precision Overcurrent Discovery Power Good for All Voltages Signal Input Under Voltage Lockout (UVLO) Thermal Shutdown Compliant with ACPI 24-pin QsopIntersil Provided Second Source (IPM6220)

application

Laptop Network Tablet Battery Power Meter

illustrate

The FAN5230 is a high-efficiency, high-accuracy multi-output voltage regulator for battery-powered applications such as notebook computers. It integrates three width modulated switching regulator controllers and two linear regulators to convert the 5.4V to 24V voltage used by the notebook battery power input circuit around the microprocessors in these systems. The two main pwm controllers in the fan5230 use synchronous mode rectification, providing 3.3V and 5V AT over 5A each. They are phased out to reduce input ripple current. The utilization of feedback in the input and output voltages in current mode control allows fast and stable loop response changes over a wide input and output range. Normal operation and hysteretic pwm control Light load control provides greater than 95% input and output variation over a wide range. This third pwm controller produces 12v at 120ma. Proprietary technology is used to accurately measure [±1%] of output current using the rds(on) of an external mosfet, eliminating external current sense resistor board space and reducing BOM cost. Two integrated linear regulators provide 3.3V and 5V backup Alwayson power for light (50MA) loads. Additional FAN5230 features include overvoltage, undervoltage and overcurrent monitors and thermal shutdown protection. When the soft-start is complete, all outputs are within ±10% of their settings.

Function description

The fan5230 is a high-efficiency, high-precision dc/dc controller for notebook computers and other portable applications. It provides all the voltages required by the system electronics: 5V, 3.3V, 12V, and 3.3V-always and 5V-always. , Input and output voltage feedback in current mode control allowing wide input and output changes. The current sense is based on mosfet rds, on providing maximum efficiency while also allowing the use of high precision sense resistors. The 3.3V and 5V switching regulator outputs of the 3.3V and 5V architectures of the FAN5230 are generated from the unregulated input voltage using a synchronous buck converter. Both high-side and low-side MOSFETs are n-channel. The 3.3V and 5V switches have current sensing and set the output overcurrent threshold with a mosfet RDS, turn on. Each converter has a voltage-sensing feedback pin, the pin that shuts down the converter, and the boost voltage used to drive the high-side mosfet. If not using a 5V switch, connect SDN5 (pin 17) to SGND (pin 14). If not using a 3.3V switcher, connect SDN3.3 (pin 11) to SGND (pin 14). The following will discuss the internal block diagram of the design integrated circuit of FAN5230. 3.3V and 5V PWM current sensing peak current detection is done on the low side driver because the duty cycle is very low on the high side mosfet. This samples the current 50ns after power-on and maintains that value for current feedback and overcurrent limiting. 3.3v and 5v pwm loop compensation Fan 5230's 3.3V and 5V control loop functions as follows for stability of voltage mode and current feedback. Each of them has an independent voltage feedback pin as shown. They use voltage feedforward to guarantee loop rejection of input voltage changes: that is, the (pulse width modulation) ramp amplitude varies with the input voltage. Control loop compensation uses current mode feedback compensation entirely internally. This scheme allows bandwidth and phase margin to be almost independent of output capacitance and esr.

3.3V and 5V undervoltage protection When the output voltage of 3.3V or 5V drops below 75% of nominal, both converters are undervoltage (UV) protected, after a 2µs delay. In undervoltage protection, the high-side and low-side MOSFETs are turned off. Once triggered, the undervoltage protection remains on until power is cycled or the SDWN pin is reset. 12V Architecture The 12V converter is a traditional non-isolated flyback (also known as a "boost" converter). The input voltage to the converter is the +5V switcher output, so +12V can only be present if +5V is present. Also, if the external mosfet is off, the output of the +12V converter is +5V, not zero. In turn will provide a non-zero output for the 12V regulator. To completely turn off the 12V regulator, an external p-channel mosfet or an ldo regulator with switch control can be used. If the ldo uses 12v, the boost should use an external resistor to set the converter to 13.2V to split the network. If not using a 12V "boost" converter, connect VFB12 (pin 15) to 5V - always (pin 6). The 12V loop compensated 12V converter should operate in discontinuous conduction mode. In this mode, if a capacitor with appropriate esr value is selected. A 68 UF tantalum rated ripple current of 500mA, 95MΩ is recommended here. 12V Protection The 12V converter is protected against overvoltage. If the 12V feedback is 10–15% higher than the nominal voltage, the comparator forces the mosfet off until the voltage falls below the comparator threshold. The 12V converter is also protected against overcurrent. If a short to A pulls the output below 9V, all switching converters go into UV protection after a 2 microsecond delay. UV protection, all mosfets are off. Once the UV protection is triggered, it remains on until the input power is recycled or the SDWN is reset. 12V Soft Start and Sequencing The 12V output starts simultaneously with the 5V output. A softly rising 5V output automatically produces a softly rising 12V output. The duty cycle of the 12V PWM is limited to prevent excessive current consumption. The voltage of the 12V supply must be higher than the UVLO limit (9V) (3.75V) when 5V is above its UVLO to avoid soft start. 5V/3.3V-Always run 5V-Always powered by an on-chip linear regulator or via the VFB pin of an internal switch 5V switch power supply. 5V - Always the power supply should be separated from ground using a 10µf capacitor. When the 5V switching power supply is turned off, or its output voltage is not within tolerance, the 5V-ALWAYS switch is turned on and the linear regulator is turned on. When the 5V switching power supply is running and the output voltage is within the specified range, the linear regulator is turned off and the switch is turned on. The switch has a low enough resistance, 5V at max current - always powered, and the output voltage is regulated within spec. 3.3V - always generated by the linear regulator internally connected to 5V - always. 3.3V - Always power should be separated from ground using a 10µf capacitor. The purpose of the two total supplies (the combined current is specified not to exceed 50 mA) is to provide power to the system microcontroller (Class 8051 ) and other integrated circuits that require a backup power supply. Microcontroller also because another IC can work on 5V or 3.3V is always the case, so the FAN5230 provides both. 5V/3.3V-Always protected Both internal linear regulators are current-limited under-voltage protection. Once all trigger protection outputs are off until power cycle or SDWN shutdown reset. Power is good when both pwm buck converters are above the specified threshold. No other regulator is monitored by force very well. At least 10 microseconds (tw) when feeling down

The error amplifier output voltage is clamped during load transients, allowing the error amplifier voltage to advance at full speed. After two clock cycles, if the amplifier is still out of voltage range, the duty cycle (DC) is clamped. The DC clamp automatically limits overcurrent under abnormal conditions, including short circuits.

If the die temperature of the fan 5230 exceeds a safe limit, the IC shuts down automatically. When the over temperature (OT) event ends, the IC resumes normal operation. There is a 25°C thermal hysteresis between shutdown and startup. If the input voltage is below the uvlo threshold, the FAN5230 automatically shuts down as long as the input voltage is below the threshold.