AcelaMicro Power Management ICs

Switching regulators like the ACM34063 provide high efficiency (85-95%) by storing energy in inductors, making them ideal for battery-powered applications and large input-output voltage differentials. However, they generate switching noise and require external inductors. LDOs like the ACM7805 offer simplicity, low noise, and fast transient response but dissipate excess power as heat. Choose switching regulators for efficiency-critical applications and LDOs for noise-sensitive analog circuits or small voltage drops.

Use switching regulators for efficiency and large voltage drops. Use LDOs for low noise and small voltage differentials.

AcelaMicro DC-DC converters achieve efficiencies of 85% to 95% depending on input voltage, output voltage, and load current. The ACM34063 synchronous buck converter achieves peak efficiency of 94% at moderate loads. Efficiency is typically highest at 50-80% of rated load current. At light loads, efficiency decreases due to quiescent current and switching losses. At heavy loads, conduction losses in the MOSFETs and inductor become significant. For battery-powered applications, consider the efficiency at your typical operating point rather than peak efficiency.

Expect 85-95% efficiency. Check efficiency curves at your operating point for battery applications.

LDO power dissipation is calculated as Pd = (Vin - Vout) × Iout + (Vin × Iquiescent). The dominant term is (Vin - Vout) × Iout. For example, with Vin = 5V, Vout = 3.3V, and Iout = 200mA, dissipation is (5 - 3.3) × 0.2 = 0.34W. Calculate junction temperature as Tj = Ta + (Pd × θja). Ensure Tj remains below the maximum rating (typically 125°C or 150°C). For high dissipation applications, consider switching regulators or LDOs with thermal pads for better heat sinking.

Calculate dissipation using Pd = (Vin - Vout) × Iout. Verify junction temperature is within limits.

PSRR (Power Supply Rejection Ratio) measures how well an LDO rejects noise and variations on its input from appearing at the output. It is expressed in dB, with higher values indicating better rejection. For example, a PSRR of 80 dB at 1 kHz means input noise at 1 kHz is attenuated by 10,000x. PSRR varies with frequency - typically high at low frequencies but decreasing at higher frequencies. For powering sensitive analog circuits like ADCs and RF components, high PSRR at the frequencies of interest is critical. The ACM7805 offers excellent PSRR of 80 dB at 1 kHz.

Select LDOs with high PSRR at frequencies present in your application. Check PSRR curves, not just single points.

Inductor selection involves balancing ripple current, size, and cost. Calculate minimum inductance using L = (Vout × (Vin - Vout)) / (Vin × fsw × ΔIL), where fsw is switching frequency and ΔIL is inductor ripple current (typically 20-40% of output current). Higher inductance reduces ripple current but increases size and cost. The inductor must have saturation current rating higher than the peak current (Iout + ΔIL/2). DCR (DC resistance) affects efficiency - lower DCR is better. Shielded inductors reduce EMI. For AcelaMicro's ACM34063 at 1A output, a 10μH inductor with 2A saturation current and <100mΩ DCR is typical.

Size inductor for 20-40% ripple current. Ensure saturation current rating exceeds peak current.