JAJSPV2 データシート

JAJSPV2 august 2023 TPSM8S6C24

PRODUCTION DATA

パッケージ・オプション

メカニカル・データ（パッケージ｜ピン）

MOY|45
- MPQF759

サーマルパッド・メカニカル・データ

発注情報

jajspv2_oa

8.3.1.2 Current Error Integrator

The current error integrator adjusts the modulator control voltage to match the sensed inductor current, I_sns, to the current voltage at the VSHARE pin. The integrator is tuned through the the following parameters in (B1h) USER_DATA_01 (COMPENSATION_CONFIG):

GMI
RVI
CZI
CPI
CZI_MUL

Thanks to the natural integration of the 1/f function of the current control gain, the bandwidth of the current control loop can be adjusted with the mid-band gain of the integrator, GMI × RVI.

The current loop crossover occurs at the frequency when the full loop gain is equal to 1 according to Equation 3:

Equation 3.

Solving for the mid-band gain of the current loop, the user finds Equation 4:

Equation 4.

While the Nyquist Theorem suggests that a bandwidth of (½)* f_SW is possible, inductor tolerances and phase delays in the current sense, modulator, and H-bridge power FETs make f_SW/4 a more practical target, which simplifies the target current loop mid-band gain to achieve a current loop bandwidth of f_SW/4 to Equation 5:

Equation 5.

An integrator from DC to the low-frequency zero, RVI × CZI, compensates for the valley voltage of the modulator ramp and the nominal offset of the output voltage. A high-frequency filter pole, RVI × CPI between half the switching frequency and the switching frequency reduces high-frequency noise from VSHARE and minimizes pulse-width jitter.

To avoid loop interactions, the integrating zero frequency must be below the voltage loop crossover frequency, while the high-frequency pole must be between 1/2 the switching frequency and the switching frequency to limit high-frequency noise and jitter in the current loop without imposing additional phase loss in the voltage loop.

The closed loop average current mode control allows the current sense amplifier, on-time modulator, H-bridge power FETs, and inductor to operate as a transconductance amplifier with forward gain of 1/CSA or 162.5 A/V with a bandwidth equal to F_coi.