VPSC VPC28C44

VPCx8C4x is a high-performance current-mode universal PWM controller designed using advanced BCD semiconductor process technology, featuring low power consumption, fast current sensing, and a high programmable maximum operating frequency.

The internally implemented circuits include: a undervoltage lockout (UVLO) with startup current as low as tens of microamps; a pulse-width modulation (PWM) fast comparator providing current limit control, with total propagation delay from comparison to output as low as 30nS; a fast-comparing oscillator enabling a programmable maximum frequency of 1MHz; an error amplifier whose non-inverting input is connected to a ±1% precision reference trimmed and calibrated; a push-pull output stage comprised of NMOS and PMOS transistors capable of delivering a high-level output equal to the device supply voltage; and additional internal circuitry to ensure latched operation.

Notably, the VPCx8C4x series incorporates an internal clamp circuit. When VDD rises to approximately 19V, its current gradually increases with voltage, reaching a maximum of 14mA (typical) at 24.7V. Under normal operating conditions, the device operates below 19V with low power dissipation, accommodating a wider temperature range. When the auxiliary supply voltage is excessive, this clamp prevents VDD from rising further, avoiding overvoltage on the power transistor gate.

The VPCx8C4x offers multiple package options, temperature range options, maximum duty cycle options, and selectable turn-on/turn-off thresholds and hysteresis ranges. Devices with higher turn-on or turn-off hysteresis are ideal for off-line power supplies, while devices with narrower hysteresis ranges are suited for DC-DC applications. The VPC28C4x has an operating temperature range of -40°C to 105°C, and the VPC38C4x has an operating temperature range of -25°C to 85°C.

The VPCx8C4x series control ICs provide all the functions required to implement AC-DC or DC-DC fixed-frequency current-mode control solutions with a minimum number of external components, offering strong versatility. Internally integrated functions include: UVLO, voltage reference, startup circuitry with less than 100uA, precision reference for the error amplifier input, logic ensuring latched operation, a PWM comparator for current limit control, and an output stage comprised of PMOS and NMOS transistors for sourcing and sinking high peak currents. The output stage, suitable for driving N-channel MOSFETs, is low in the off state.

The primary distinctions among these series are the UVLO thresholds, acceptable ambient temperature range, and maximum duty cycle. The VPCx8C42 and VPCx8C44 devices feature typical UVLO thresholds of 14.6V (ON) and 8.7V (OFF), making them well suited for off-line AC-DC applications. The VPCx8C43 and VPCx8C45 devices have corresponding typical thresholds of 8.5V (ON) and 7.7V (OFF), making them well suited for regulated input voltages used in DC-DC applications. The VPCx8C40 and VPCx8C41 devices feature typical UVLO thresholds of 7.0V (ON) and 6.6V (OFF), making them well suited for DC-DC applications with lower input voltages. The VPCx8C42, VPCx8C43, and VPCx8C40 devices operate with duty cycles approaching 100%. The VPCx8C44, VPCx8C45, and VPCx8C41 achieve a duty cycle range of 0% to 50% by incorporating an internal flip-flop that blanks the output every other clock cycle. The recommended operating temperature range is –40°C to 105°C for the VPC28C4x series and –25°C to 85°C for the VPC38C4x series.

• Start-up current as low as 50uA, max 100uA; operating current only 2.7mA at 52kHz
• CS fast comparator with propagation delay as low as 30nS
• Maximum operating frequency 1MHz; error amplifier reference voltage with ±1% accuracy
• Rail-to-rail output voltage OUT; with 1nF capacitor on OUT, output rise time 30nS, fall time 20nS
• Cycle-by-cycle current limiting
• Trimmed oscillator discharge current
• Built-in clamp absorption circuit

• Switching regulator of any polarity
• Transformer-coupled DC-DC converter BMS auxiliary power supply