Break up long equation with square brackets into multiple lines

Question

I'm having trouble splitting the portion of the equation within square brackets into two lines. How can it be done?

\documentclass{article}
\usepackage{amsmath}

\begin{document}


\begin{align}
\ \frac{d\langle  v_{dcL} \rangle  _0}{dt}&=\frac{1}{C_{dcL}}\Big[2{\langle  S_{D2} \rangle  ^R_1\langle  i_{tp} \rangle  ^R_1+\langle  S_{D2} \rangle  ^I_1\langle  i_{tp} \rangle  ^I_1-\langle  S_{i1} \rangle  ^R_1\langle  i_{fi1} \rangle  ^R_1 -\langle  S_{i1} \rangle  ^I_1\langle  i_{fi1} \rangle  ^I_1}\Big] \\
\end{align}

\end{document}

Answer 1

Do it manually, with

\documentclass{article}
\usepackage{amsmath}
\begin{document}

\begin{align}
\ \frac{d\langle  v_{dcL} \rangle  _0}{dt}&=\frac{1}{C_{dcL}}\Big[2 
\langle  S_{D2} \rangle  ^R_1\langle  i_{tp} \rangle  ^R_1+\\
&\langle  S_{D2} \rangle  ^I_1\langle  i_{tp} \rangle  ^I_1-\langle 
 S_{i1} \rangle  ^R_1\langle  i_{fi1} \rangle  ^R_1 -\langle  S_{i1}
  \rangle  ^I_1\langle  i_{fi1} \rangle  ^I_1 \Big] 
\end{align}

\end{document}

and output is: